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"© 2002 Encyclopaedia Britannica, Inc.

Population (2005 est.): 2,409,000. Capital:

Muscat. The Omanis are predominantly Arab and tribal in organization. There are also many migrant workers from South Asia and eastern Africa who reside there.

Languages: Arabic (official), others. Religions: Islam (official); also Hin¬ duism, Christianity. Currency: Omani rial. Oman is a hot, arid country with high humidity along the coast. The Hajar Mountains parallel the shore of the Gulf of Oman, reaching an elevation of more than 10,000 ft (3,000 m). A broad expanse of sandy desert covers much of the country. Oman has a developing mixed economy, and the production and export of petroleum is its largest sector. It is a hereditary monarchy, with an advisory council; its head of state and government is the sultan. Human habitation dates to about the 3rd millennium bc. The Omani tribal system dates to Arab migration during the 2nd century ad. It was ruled by imams (Muslim religious lead¬ ers) of the Ibad! sect from the early Islamic period (mid-8th century) until the 12th century, when local rule was established. The Portuguese con¬ trolled the coastal areas c. 1507-1650, when they were expelled. The Al Bu SaTd, a dynasty founded in the mid-18th century, still rules Oman. The kingdom expanded into eastern Africa in the 18th- 19th century, where its capital was at Zanzibar. Oil was discovered in 1964. In 1970 the sultan was

© 2006 Encyclopaedia Britannica, Inc.

1408 I Oman ► Ondcicitje

deposed by his son, who began a policy of modernization, and under him Oman joined the Arab League and the United Nations. In the First Persian Gulf War, Oman cooperated with the forces allied against Iraq. It subse¬ quently continued to expand its foreign relations.

Oman, Gulf of Northwestern arm of the Arabian Sea, between the eastern part of the Arabian Peninsula and Iran. It is about 230 mi (370 km) wide and 340 mi (545 km) long and connects with the Persian Gulf through the Strait of Hormuz. It is the only entrance to the Persian Gulf from the Arabian Sea and Indian Ocean and is important as a shipping route for the oil-producing area around the Persian Gulf.

Omar, Mosque of See Dome of the Rock

Omar Khayyam \ I o- I mar- 1 k!- , yam\ byname of Ghiydth al-DTn Abu al-Fath ‘Umar ibn Ibrahim al-Neyshaburl al-Khayyaml (b. May 18, 1048, Neyshabur, Khorasan—d. Dec. 4, 1131, Neyshabur) Persian poet, mathematician, and astronomer. Educated in the sciences and philosophy, he was renowned in his country and time for his scientific achievements, but few of his prose writings survive. His verses attracted little attention until his roba l Tyat (“quatrains”) were loosely translated into English by Edward FitzGerald and published in 1859. Many of the quatrains (each of which was intended as an indepen¬ dent poem) are of doubtful attribution; most scholars agree on the authen¬ ticity of about 50, with controversy over some 200 others.

ombudsman Vam-.budz-msnV Swedish representative Represen¬ tative assigned by a large organization or a government to investigate citi¬ zen complaints and suggest solutions. An ombudsman’s office was established by the Swedish constitution of 1809. The idea soon spread to other Scandinavian countries and later to New Zealand, Britain, Germany, Israel, and some states or provinces in the U.S., Australia, and Canada. An ombudsman’s responsibility is to receive and investigate complaints and to serve as an independent and impartial arbiter in recommending what may be done to satisfy the complainant or in explaining why no action is necessary. Ombudsmen are now used in universities, corpora¬ tions, municipalities, and institutions such as hospitals.

Omdurman V.am-dor-'manN City (pop., 1993 est.: 1,267,000), east- central Sudan. It is situated on the left bank of the Nile River just below the confluence of the Blue and White Niles. It was an insignificant village until the victory of al-MAHDi over the British in 1885. It grew rapidly after al-Mahdl and his successor, c Abd Allah, made it their capital. It was captured by Anglo-Egyptian forces in 1898 but continued to develop into the cultural, religious, and commer¬ cial centre of The Sudan. Sites of interest include c Abd Allah’s house (now a museum) and the tomb of al-Mahdl.

Omega Centauri \o-'ma-g9-sen- 'tor-I\ Brightest globular cluster, located in the constellation Centau- rus. It has a magnitude of 3.7 and is visible to the unaided eye as a faint luminous patch. One of the nearer globular clusters (about 17,000 light- years away), it is estimated to con¬ tain hundreds of thousands of stars, including several hundred variable stars. John Herschel (see Herschel family) was the first to recognize it as a star cluster and not a nebula.

omen Observed phenomenon that is interpreted as signifying good or bad fortune. The many and varied omens that the ancients noted included lightning, cloud movements, the flights of birds, and the paths of sacred animals. Each type of omen was gauged according to specific meaning¬ ful characteristics, such as the kinds of bird in flight or the direction of flight in relation to the observer.

Ometecuhtli V.o-ma-'ta-.kut-leX Aztec deity, the Lord of Duality or Lord of Life. With his female counterpart, Omecihuatl (Lady of Duality), he lived in Omeyocan, the 13th and highest Aztec heaven. He was repre¬ sented by symbols of fertility, and his image was adorned with ears of

com. He was the only Aztec god to have neither a temple nor a formal cult. Seeing him as remote in the heavens, the Aztecs assumed he would never interact with them directly, but they felt his presence in rituals and in the rhythms of nature.

omnivore Vam-ns-.voiA Animal that eats both plant and animal matter. Most omnivorous species do not have highly specialized food-processing structures or food-gathering behaviour. Many animals generally consid¬ ered carnivores are actually omnivorous; for example, the red fox eats fruits and berries as well as mammals and birds. See also herbivore.

Omsk \'6msk\ City (pop., 2002: 1,133,900), west-central Russia. It is located in southwestern Siberia at the confluence of the Irtysh and Om riv¬ ers. Founded in 1716 as a military stronghold, Omsk became a city in 1804. It remained the headquarters of the Siberian Cossacks until the late 19th century. In 1918-19 it was the seat of the anti-Bolshevik govern¬ ment of Adm. Aleksandr Kolchak. Its growth was spurred by the building of the Trans-Siberian Railroad in the 1890s and the onset of World War II. Pipelines from the Volga-Urals and western Siberian oil fields supply the refinery, and the petrochemical industry is also is important.

On See Heliopolis

Onassis, Aristotle (Socrates) (b. Jan. 20, 1906, Smyrna, Tur.—d. March 15, 1975, Neuilly-sur-Seine, near Paris, France) Greek shipping magnate and international businessman. The son of a tobacco dealer, he started a tobacco-importing business in Buenos Aires, Arg. He was made consul general after negotiating a trade agreement for the Greek govern¬ ment. A millionaire by age 25, he bought his first freight ships in 1932. In the 1940s and ’50s his fleet grew until it was larger than the navies of many countries. He acquired business interests in Monte Carlo, and from 1957 to 1974 he owned and operated Olympic Airways, the Greek national airline. He conducted a long affair with Maria Callas, and in 1968 married Jacqueline Kennedy (see Jacqueline Kennedy Onassis).

Onassis, Jacqueline Kennedy orig. Jacqueline Bouvier (b.

July 28, 1929, Southampton, N.Y., U.S.—d. May 19, 1994, New York, N.Y.) U.S. first lady, socialite, and editor. After graduating from George Washington University in 1951 she took a job as a reporter-photographer at the Washington Times-Herald. In 1953 she married Sen. John F. Kennedy, who became president in 1961. As first lady, she restored the White House to its original Federal style and conducted a televised tour of the residence. Her graciousness, elegance, and beauty endeared her to the American public, and her broad culture and ease in speaking Spanish and French impressed foreign leaders. After her husband’s assassination in 1963 she moved to New York with their children, Caroline (b. 1957) and John, Jr. (1960-99). In 1968 she married Aristotle Onassis. After his death in 1975, she returned to New York, where she became a book editor.

Onate \on-'ya-ta\, Juan de (b. 15507, New Spain—d. 1630) Spanish conquistador. The son of wealthy parents in Zacatecas, New Spain, he married a granddaughter of Hernan Cortes. He received permission to govern the colony of New Mexico, which he founded in 1598. He sent exploring parties throughout the American Southwest to search for gold and led an expedition into present-day Kansas in 1601. Still searching for gold, he explored the region west to the Colorado River and south to the Gulf of California (1604). He resigned in 1607. Tried for his brutal treat¬ ment of Indians and settlers while governor, he was found guilty and exiled from the colony in 1614.

onchocerciasis See river blindness

oncogene \'aq-ko-Jen\ Gene that can cause cancer. It is a sequence of DNA that has been altered or mutated from its original form, the proto¬ oncogene (see mutation). Proto-oncogenes promote the specialization and division of normal cells. A change in their genetic sequence can result in uncontrolled cell growth, ultimately causing the formation of a cancerous tumour. In humans, proto-oncogenes can be transformed into oncogenes in three ways: point mutation (alteration of a single nucleotide base pair), translocation (in which a segment of the chromosome breaks off and attaches to another chromosome), or amplification (increase in the num¬ ber of copies of the proto-oncogene). Oncogenes were first discovered in certain RETROViRUSes and were later identified as cancer-causing agents in many animals. See also J. Michael Bishop; Harold Varmus.

Ondaatje \an-'da-cha\, (Philip) Michael (b. Sept. 12, 1943, Colombo, Ceylon) Sri Lankan-born Canadian novelist and poet. He immi¬ grated to Montreal at age 19 and attended the University of Toronto and

The tomb of al-Mahdl in Omdurman, The Sudan.

CHARLES BEERY/SHOSTAL ASSOCIATES

© 2006 Encyclopaedia Britannica, Inc.

Onega ► ontology I 1409

Queen’s University. His fascination with the American West led to one of his most celebrated works, the pastiche The Collected Works of Billy the Kid (1970). His novel The English Patient (1992, Booker Prize; film, 1996) won him international recognition; it was followed by Anil’s Ghost (2000). His musical poetry and prose are a blend of myth, history, jazz, memoirs, and other forms.

Onega \3-'nye-g3\, Lake Lake, northwestern Russia. Located between Lake Ladoga and the White Sea, it is the second-largest lake in Europe. It has an area of 3,753 sq mi (9,720 sq km) and is 154 mi (248 km) long. It empties into the Svir River and is frozen for about half of each year. It is connected with the Baltic and White seas by canal and with the Volga River basin by a waterway, enabling it to play an important part in inter¬ national trade and transport.

Oneida \o-'nI-d3\ North American Indian people living mainly in what is now central New York and Wisconsin, U.S., and Canada. They consti¬ tute one of the original five nations of the Iroquois Confederacy. Their language is Iroquoian. They call themselves Oneyoteaka, meaning “People of the Standing Stone.” The Oneida were semisedentary and practiced com agriculture. Longhouses sheltered families related through maternal descent and belonging to one of three clans. Bear, Turtle, or Wolf. Each community had a local council that guided the chief or chiefs. The Oneida supported the colonist cause in the American Revolution and were attacked by the pro-British Iroquois under Joseph Brant. By the mid- 19th century most Oneida had dispersed. They number some 12,000.

Oneida Community Utopian religious community founded by John H. Noyes in Oneida, N.Y., in 1848. Noyes, who believed that the Second Coming of Jesus Christ had occurred in ad 70, and his disciples formed their first religious society in Putney, Vt., in 1841 in order to establish the millennial kingdom. Their practice of “complex marriage,” according to which each adult community member was married to each adult of the opposite sex, aroused the hostility of the townspeople, and they were obliged to move to Oneida. The Oneida group lived communally and flourished for 30 years, supporting itself by farming and manufacturing steel traps, silverware, and other items. The community broke up in 1879, and two years later the remaining members reorganized it as a commer¬ cial enterprise, which is noted for the manufacture of silver plate.

O'Neill, Eugene (Gladstone) (b. Oct. 16, 1888, New York, N.Y., U.S.—d. Nov. 27, 1953, Boston, Mass.) U.S. playwright. The son of a touring actor, he spent an itinerant youth as a seaman, heavy drinker, and derelict, then began writing plays while recovering from tuberculosis (1912). His one-act Bound East for Cardiff (1916) was produced by the experimental Provincetown Payers, which also staged his other early plays (1916-20). Beyond the Horizon was produced on Broadway in 1920, earning him his first Pulitzer Prize. Enormously prolific, he often wrote about tortured family relationships and the conflict between idealism and materialism. Soon recognized as a major dramatist, he became widely translated and produced. His many plays of the 1920s include The Emperor Jones (1921), The Hairy Ape (1922), Anna Christie (1922; Pulitzer Prize), Desire Under the Elms (1925), The Great God Brown (1926), and Strange Interlude (1928; Pulitzer Prize). Among his later plays are Mourning Becomes Electra (1931), Ah! Wilderness (1933; his only comedy). The Iceman Cometh (1946), and the autobiographical Long Day’s Journey into Night (produced 1956; Pulitzer Prize), considered his masterpiece. O’Neill was awarded the Nobel Prize for Literature in 1936, the first U.S. playwright so honoured.

O'Neill, John (b. March 8, 1834, County Monaghan, Ire.—d. Jan. 7, 1878, Omaha, Neb., U.S.) Irish-born military leader of the American branch of the Fenians, a secret Irish nationalist society. He arrived in the U.S. in 1848 and settled in Tennessee, where he joined the Fenians. A supporter of its scheme to invade Canada to win Irish freedom from Brit¬ ain, in 1866 he led a group of 600 men across the Niagara River and cap¬ tured Fort Erie before fleeing back to the U.S. In 1870 he led a raid along the Vermont border that was repulsed; he led another raid on Manitoba in 1871. See also John O'Mahony.

Onin War Vo-nin\ (1467-77) Civil war in central Japan that destroyed the remnants of central governmental authority and led to a century of warfare. The conflict sprang from a succession dispute, with one power¬ ful clan supporting the brother of the Ashikaga shogun (military ruler) and another supporting the shogun’s infant son. It ended in stalemate, but clans across Japan became involved in hopes of increasing their territory through victory. The nation was at last reunified in the late 16th and early

17th centuries under Oda Nobunaga, Toyotomi Hideyoshi, and Tokugawa Ieyasu. See also Muromachi period; Warring States period.

onion Herbaceous biennial plant (. Allium cepa) of the lily family, prob¬ ably native to South Asia but now grown worldwide, and its edible bulb. Among the hardiest and oldest garden-vegetable plants, onions bear a cluster of small, greenish white flowers on one or more leafless stalks. The leaf base swells to form the underground mature edible onion. Onions are pungent; because they contain a sulfur-rich volatile oil, peeling or slicing them can cause a person’s eyes to tear. Onions vary in size, shape, colour, and pungency.

Though low in standard nutrients, they are valued for their flavour.

Onions have been claimed to cure colds, earaches, and laryngitis and have been used to treat animal bites, powder burns, and warts; like their close relative garlic, they are being studied for other suspected beneficial qualities. See also allium.

Onnes, Heike Kamerlingh See Heike Kamerlingh Onnes

Onsager Von-.sa-gorV, Lars (b. Nov. 27, 1903, Oslo, Nor.—d. Oct. 5, 1976, Coral Gables, Fla., U.S.) Norwegian-born U.S. chemist. He immi¬ grated to the U.S. and taught principally at Yale University. His develop¬ ment of a general theory of irreversible chemical processes, described as the “fourth law of thermodynamics,” gained him a 1968 Nobel Prize. He also applied the laws of thermodynamics to systems not in equilibrium. His expla¬ nation of the movement of ions in solution as related to turbulence and fluid density had a major effect on the development of physical chemistry.

Ontario Province (pop., 2001: 11,874,400), the second largest in Canada. Situated between Hudson Bay and James Bay and the St. Lawrence RiVER-Great Lakes chain, it is bordered by the U.S. and the Canadian provinces of Quebec and Manitoba. It covers 412,581 sq mi (1,068,580 sq km). Its capital is Toronto. Before European settlement, the area was inhabited by Iroquois and Algonquin Indian tribes. In the 17th century it was visited by French explorers and missionaries. It passed to the British in 1763 after the French and Indian War. It was the scene of many battles in the War of 1812. The area was known as Canada West from 1841 until 1867, when it became one of four provinces of the new Dominion of Canada. Northern Ontario has a rocky and rugged terrain with thick forests, bogs, lakes, and extensive mineral reserves. Southern Ontario is an important farming and industrial region and is the centre of Canada’s population and urban development. Ottawa, the national capital, is also in Ontario.

Ontario, Lake Smallest and easternmost of the Great Lakes of North America. Bounded by New York and Ontario, and with the U.S.-Canada border passing through it, the lake is roughly elliptical; its major axis, 193 mi (311 km) long, lies nearly east to west, and its greatest width is 53 mi (85 km). The Niagara River is the lake’s main feeder. There are five islands at its eastern end, where the lake discharges into the St. Lawrence River near Kingston, Ont. The Welland Canal and the Niagara River connect it to Lake Erie to the southwest. It was visited by Samuel de Champlain in 1615; its early French name was Lac Frontenac. Ports on the lake include Toronto and Hamilton, Ont., and Rochester and Oswego, N.Y.

ontological argument Argument that proceeds from the idea of God to the reality of God. It was first clearly formulated by St. Anselm in his Proslogion (1077-78); a later famous version is given by Rene Descartes. Anselm began with the concept of God as that than which nothing greater can be conceived. To think of such a being as existing only in thought and not also in reality involves a contradiction, since a being that lacks real existence is not a being than which none greater can be conceived. A yet greater being would be one with the further attribute of existence. Thus the unsurpassably perfect being must exist; otherwise it would not be unsurpassably perfect. This is among the most discussed and contested arguments in the history of thought.

ontology Theory of being as such. It was originally called “first phi¬ losophy” by Aristotle. In the 18th century Christian Wolff contrasted ontology, or general metaphysics, with special metaphysical theories of

© 2006 Encyclopaedia Britannica, Inc.

1410 I onychophoran ► opera

souls, bodies, or God, claiming that ontology could be a deductive dis¬ cipline revealing the essences of things. This view was later strongly criticized by David Hume and Immanuel Kant. Ontology was revived in the early 20th century by practitioners of phenomenology and existentialism, notably Edmund Husserl and his student Martin Heidegger. In the English- speaking world, interest in ontology was renewed in the mid-20th century by W.V.O. Quine; by the end of the century it had become a central dis¬ cipline of analytic philosophy. See also idealism; realism; universal.

onychophoran V.a-ni-'ka-fo-ronX Any of about 90 species of free- living terrestrial invertebrates in the class Onychophora (sometimes con¬ sidered a phylum). They are sometimes called velvet worms for their velvety skin. The common genus Peripatus occurs in the West Indies, Central America, and northern South America. Onychophorans are slen¬ der and segmented; each segment has a pair of short legs. Species range from 0.6 to 6 in. (14-150 mm) long. They live in humid, hidden spots: in forest litter, wood crevices, termite nests, or the soil, sometimes to a depth of more than 3 ft (1 m). They use their jaws to open captured prey (often small insects) and suck out the juices.

onyx \'a-niks\ Striped, semiprecious variety of the silica mineral agate with white and black alternating bands. Other varieties include carnelian onyx, with white and red bands, and sardonyx, with white and brown bands. Its properties are the same as those of quartz. Onyx is used in carved cameos and intaglios because its layers can be cut to show a colour contrast between the design and the background. It is found worldwide, but chiefly in India and South America.

Oort cloud Vast spherical cloud of small, icy bodies orbiting the Sun at distances ranging from about 0.3 light-year to one light-year or more that is probably the source of most long-period comets. In 1950 the Dutch astronomer Jan Hendrik Oort (1900-92) noted that no comets have orbits that would indicate an interstellar origin. He proposed that the Sun is sur¬ rounded by billions of these objects, which are only occasionally detect¬ able when they enter the inner solar system. The Oort cloud is believed to be composed of primordial bodies dating from the formation of the solar system (see solar nebula). Whether the Oort cloud merges, in its inner region, into the disk-shaped Kuiper belt is not known.

Op art or Optical art Branch of mid-20th-century geometric abstract art that deals with optical illusion. Op art painters devised complex opti¬ cal spaces by manipulating repetitive forms such as parallel lines, check¬ erboard patterns, and concentric circles or by creating chromatic tension from the juxtaposition of complementary colours, thereby creating the illusion of movement. Principal artists of the Op movement in the late 1950s and the ’60s include Victor Vasarely, Bridget Riley (b. 1931), and Larry Poons (b. 1937).

opal A hydrated, noncrystalline silica mineral used extensively as a gem¬ stone. Its chemical composition is similar to that of quartz but generally with a variable water content. Pure opal is colourless, but impurities generally give it various dull colours ranging from yellow and red to black. Black opal is especially rare and valuable. White opal and fire opal, characterized by yellow, orange, or red colour, are much more common. Various forms of common opal are widely used as abrasives, insulation material, and ceramic ingredients. Opal is most abundant in volcanic rocks, especially in areas of hot-spring activity. The finest gem opals have been found in Australia; other areas that yield gem material include Japan, Mexico, Honduras,

India, New Zealand, and the U.S.

OPEC in full Organization of the Petroleum Exporting Countries Multinational organiza¬ tion established in 1960 to coordinate the petroleum production and export policies of its members. Iran, Iraq, Kuwait, Saudi Arabia, and Venezuela were the original members; they were joined by Qatar (1961), Indonesia and Libya (1962), Abu Dhabi (1967; membership transferred to the United

Arab Emirates, 1974), Algeria (1967), and Nigeria (1971). Ecuador (1973) and Gabon (1975) are no longer OPEC members. Policy decisions are taken by consensus at its Vienna headquarters. In 1973 OPEC began a series of oil price increases in retaliation for Western support of Israel in the 1973 Arab-Israeli war, and OPEC members’ income greatly increased as a result. Internal dissent, the development of alternative energy sources in the West, and Western exploitation of oil sources in non-OPEC coun¬ tries subsequently combined to reduce the organization’s influence. OPEC countries supply about two-fifths of the world’s oil consumption and pos¬ sess about two-thirds of the world’s proven oil reserves.

open cluster or galactic cluster Any group of Population I (see Populations I and II) stars with a common origin, held together by mutual gravitation (not to be confused with a cluster of galaxies). Stars in open clusters are much more scattered than those in globular clusters. All known open clusters contain from about 10 to 1,000 or more stars (about half contain fewer than 100) and have diameters of 5-75 light-years. More than 1,000 have been discovered in the Milky Way Galaxy; well-known examples include the Pleiades and the Hyades.

Open Door policy Statement of U.S. foreign policy toward China. Issued by U.S. secretary of state John Hay (1899), the statement reaffirmed the principle that all countries should have equal access to any Chinese port open to trade. The U.S. sent notes to Britain, Germany, France, Italy, Japan, and Russia explaining the policy to prevent them from establish¬ ing separate spheres of influence in China. Their replies were evasive, but the U.S. considered them acceptances of the policy. Japan’s violation of the policy in 1937 led the U.S. to impose an oil embargo. The policy was discontinued with the communist takeover of China in 1949.

open-heart surgery Any surgical procedure opening the heart and exposing one or more of its chambers, most often to repair valve disease or correct congenital heart malformations (see congenital heart disease). Invention of the heart-lung machine (see artificial heart), which allows the heart to be stopped during surgery, made it possible. The first successful open-heart surgery was performed in the U.S. in 1953 by John H. Gib¬ bon, Jr., to close an atrial septal defect.

open-hearth process or Siemens-Martin process Steelmaking technique that for most of the 20th century accounted for most steel made in the world. William Siemens made steel from pig iron in a reverberatory furnace of his design in 1867. The same year the French manufacturer Pierre-Emile Martin (1824-1915) used the idea to produce steel by melt¬ ing wrought iron with steel scrap. Siemens used the waste heat given off by the furnace: he directed the fumes from the furnace through a brick checkerwork, heating it to a high temperature, and then used the same path to introduce air into the furnace; the preheated air significantly increased the flame temperature. The open-hearth process furnace (which replaced the Bessemer process) has itself been replaced in most industrial¬ ized countries by the basic oxygen process and the electric furnace. See also

REVERBERATORY FURNACE.

open market operation Any of the purchases and sales of govern¬ ment securities and commercial paper by a central bank in an effort to regulate the money supply and credit conditions. Open market operations can also be used to stabilize the prices of government securities. When the central bank buys securities on the open market, it increases the reserves of commercial banks, making it possible for them to expand their loans and investments. It also increases the price of government securi¬ ties, equivalent to reducing their interest rates, and decreases interest rates generally, thus encouraging investment. If the central bank sells securi¬ ties, the effects are reversed. Open market operations are usually per¬ formed with short-term government securities such as treasury bills.

opera Musical drama made up of vocal pieces with orchestral accom¬ paniment, overtures, and interludes. Opera was invented at the end of the 16th century in an attempt by the Camerata (an academy of Florentine poets, musicians, and scholars) to imitate ancient Greek drama, which was known to have been largely sung or chanted. Since no actual Greek music was known, composers had considerable freedom in reconceiving it. Imi¬ tations of Greek pastoral poetry became the basis for early opera libretti. The first operas, Dafne by Jacopo Peri (1561-1633) in 1598 and by Giuuo Caccini about the same time, are now lost; the earliest surviving opera is Peri’s Euridice (1600). They consisted of lightly accompanied vocal melody closely imitating inflected speech. Claudio Monteverdi, the great¬ est early operatic figure, composed the first masterpiece, Orfeo, in 1607; unlike its predecessors, it is scored for a small orchestra. With this work,

Black opal from Australia; in the collec¬ tion of the Department of Earth Sci¬ ences, Washington University, St. Louis, Mo.

JOHN H. GERARD

© 2006 Encyclopaedia Britannica, Inc.

operating system ► opium poppy I 1411

recitative began to be clearly distinguished from aria, an achievement that would prove decisive for opera’s future success. In France, Jean-Baptiste Lully produced a prototype for courtly opera that influenced French opera through the mid-18th century. Jean-Philippe Rameau, George Frideric Han¬ del, and Christoph Willibald Gluck were the most significant opera com¬ posers of the first two-thirds of the 18th century; their works were surpassed by the brilliant operas of Wolfgang Amadeus Mozart. In the early 19th century, Gioacchino Rossini and Gaetano Donizetti dominated Italian opera. In the later 19th century the greatest works were those of Giuseppe Verdi and Richard Wagner; the latter, with his bold innovations, became the most influential operatic figure since Monteverdi. Richard Strauss and Giacomo Puccini wrote the most popular late 19th- and early 20th-century operas. Though the death of Puccini in 1924 is often cited as the end of grand opera, new and often experimental works—by com¬ posers such as Alban Berg, Benjamin Britten, Gian Carlo Menotti, John Adams, and Philip Glass —continued to be produced to critical acclaim. Opera entered the 21st century as a vibrant and global art form. See also BALLAD OPERA; OPERETTA.

operating system (OS) Software that controls the operation of a computer, directs the input and output of data, keeps track of files, and controls the processing of computer programs. Its roles include managing the functioning of the computer hardware, running the applications pro¬ grams, serving as an interface between the computer and the user, and allocating computer resources to various functions. When several jobs reside in the computer simultaneously and share resources (multitasking), the OS allocates fixed amounts of CPU time and memory in turn or allows one job to read data while another writes to a printer and still another performs computations. Through a process called time-sharing, a large computer can handle interaction with hundreds of users simultaneously, giving each the perception of being the sole user. Modern computer oper¬ ating systems are becoming increasingly machine-independent, capable of running on any hardware platform; a widely used platform-independent operating system in use today on mainframe computers is UNIX. Most per¬ sonal computers run on Microsoft’s Windows operating system, which grew out of and eventually replaced MS-DOS. See also Linux.

operationalism In the philosophy of science, the attempt to define all scientific concepts in terms of specifically described operations of mea¬ surement and observation. The length of a rod, for example, may be defined as the number of times a certain stick can be laid end to end alongside it. Propositions that are not amenable to verification through measurement and observation are rejected as meaningless (see also logi¬ cal positivism). Operationalists rejected the idea of nature as a thing-in-itself existing behind the appearances observed in experimentation. Operation¬ alism is closely associated with the work of the U.S. physicist Percy W. Bridgman (1882-1961).

operations management See production management

operations research Application of scientific methods to manage¬ ment and administration of military, government, commercial, and indus¬ trial systems. It began during World War II in Britain when teams of scientists worked with the Royal Air Force to improve radar detection of enemy aircraft, leading to coordinated efforts to improve the entire sys¬ tem of early warning, defense, and supply. It is characterized by a sys¬ tems orientation, or systems engineering, in which interdisciplinary research teams adapt scientific methods to large-scale problems that must be modeled, since laboratory testing is impossible. Examples include resource allocation and replacement, inventory control, and scheduling of large-scale construction projects.

operator, differential See differential operator

operetta Musical drama similar to opera, usually with a romantically sentimental plot, employing songs, dances, and orchestral interludes inter¬ spersed with spoken dialogue. The modern tradition begins with Jacques Offenbach, who wrote some 90 operettas and inspired a Viennese tradi¬ tion that began with the works of Franz von Suppe and Johann Strauss. In Britain most of the 14 comic operettas (1871-96) of W.S. Gilbert and Arthur Sullivan have been enduringly popular. In the U.S. the works of such European immigrant composers as Victor Herbert and Rudolf Friml were widely popular in the early 20th century. See also musical.

operon Va-p3r-,an\ Genetic regulatory system of single-celled organ¬ isms (prokaryotes) and their viruses, in which genes coding for function¬ ally related proteins are clustered along the DNA, enabling their

expression to be coordinated in response to the cell’s needs. By provid¬ ing a means to produce proteins only when and where they are required, the operon allows the cell to conserve energy. A typical operon consists of a group of structural genes that code for enzymes involved in a meta¬ bolic pathway, such as the biosynthesis of an amino acid. A single unit of messenger RNA is transcribed from the operon and is then translated into separate proteins. Operons are controlled by various regulatory ele¬ ments that respond to environmental cues. The operon system was first proposed by Francois Jacob and Jacques Monod in the early 1960s.

Opet Vo- ,pet\ Ancient Egyptian festival of the New Year. In the celebra¬ tion of Opet, statues of Amon and Mut and their son Khons were carried down the Nile on barges in a ritual journey from their shrines at Karnak to the temple of Luxor. There the statues remained about 24 days, a fes¬ tival time for Luxor. The images were returned to Karnak by the same route in a second public appearance that closed the festival.

Ophite Va-.fit, 'o-.fnA Member of any of several Gnostic sects that flour¬ ished in the Roman empire in the 2nd century ad and for several centu¬ ries thereafter. The sects shared a dualistic theology, opposing a beneficent and entirely spiritual Supreme Being to a chaotic and evil material world. To the Ophites, the human dilemma resulted from the mixture of these conflicting spiritual and material elements in human nature. Only gnosis, the esoteric knowledge of good and evil, could redeem one from the bonds of matter. See also dualism, Gnosticism.

ophthalmology \ l af-th9l-'ma-b-je\ Medical specialty dealing with the eyes, dating to 1805. Frans C. Donders’s 1864 advances in optics allowed eyeglasses to be fitted to vision problems. The ophthalmoscope made it possible to look inside the eye and relate eye defects to internal condi¬ tions. More recent advances include eye exams, early treatment of con¬ genital defects, and eye banks to store corneas for transplants. Ophthalmologists test visual function and examine the eye for faulty development, disease, injury, degeneration, aging, or refractive errors. They prescribe treatment for eye disease and lenses for refraction and perform surgery when needed. See also optometry, visual-field defect.

Ophuls Vo-ftelsX, Max orig. Max Oppenheimer (b. May 6, 1902, Saarbriicken, Ger.—d. March 26, 1957, Hamburg, W.Ger.) German film director. An actor, stage director, and producer in Germany and Austria (1921-30), he gained renown as a film director with Liebelei (1933). He left Nazi Germany and directed popular but undistinguished films in France, Russia, Italy, and The Netherlands until 1940, when he moved to the U.S. In Hollywood he directed The Exile (1947), Letter from an Unknown Woman (1948), and The Reckless Moment (1949). He returned to France to make The Roundabout (1950), House of Pleasure (1952), and The Sins of Lola Montes (1955), considered his masterpiece. His son, Marcel (b. 1927), worked in France principally as a maker of documen¬ tary films, most notably The Sorrow and the Pity (1971), which examines French conduct under German occupation.

Opie, Eugene Lindsay (b. July 5, 1873, Staunton, Va., U.S.—d. March 12, 1971, Bryn Mawr, Pa.) U.S. pathologist. He received his M.D. from Johns Hopkins University. Early in his career, he correctly deduced that degenerative changes in the islets of Langerhans caused diabetes mel- litus and theorized that blockage of the junction of the bile and pancre¬ atic ducts caused acute pancreatitis. He later showed that tuberculosis (TB) was spread by contact, including from one family member to another. His work led to use of X-ray films to detect asymptomatic TB, the sputum test to predict the chance of its spread, and injection of heat-killed tubercle bacilli to prevent infection.

opium Organic compound, a narcotic drug known since ancient Greek times, obtained from exuded juice of immature fruit capsules of the opium poppy. Opium has legitimate medical uses, as the source of the alkaloids codeine and morphine and their derivatives. It is also used illicitly, either raw or purified as alkaloids and their derivatives (including heroin). Opium alkaloids of one type (e.g., morphine, codeine) act on the nervous system, mimicking the effects of endorphins; they are analgesic, narcotic, and potentially addicting (see drug addiction). Those of a second type, including papaverine and noscapine, relieve smooth muscle spasms and are not analgesic, narcotic, or addicting. Habitual opium use produces physical and mental deterioration and shortens life. Overdose can cause death by depressing respiration.

opium poppy Flowering plant ( Papaver somniferum) of the family Papaveraceae, native to Turkey. Opium, morphine, codeine, and heroin are

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1412 I Opium Wars ► opuntia

all derived from the milky fluid found in its unripe seed capsule. A com¬ mon garden annual in the U.S., the opium poppy bears blue-purple or white flowers 5 in. (13 cm) wide on plants about 3-16 ft (1-5 m) tall, with lobed or toothed silver-green foliage. It is also grown for its tiny nonnarcotic ripe seeds, which are kidney-shaped and grayish blue to dark blue; the seeds are used in bakery products and for seasoning, oil, and birdseed.

Opium Wars Two trading wars of the mid-19th century in China. The first (1839-42 was between China and Britain, and the second (1856-60; also called the Arrow War or Anglo-French War) was between China and a British-French alliance. Trade developed between China and Western countries from the late 16th century. The Chinese, accustomed to tribu¬ tary relationships with others, required that Westerners pay for Chinese goods with silver currency. To offset a growing negative flow of silver at home, the British created a market for opium in China and began import¬ ing it there illegally. As demand for opium grew, China tried to stop the practice, and hostilities broke out. Britain quickly triumphed, and the resultant Treaty of Nanjing (Nanking; 1842; the first of a series of unequal treaties between China and Western countries and, eventually, Japan) was a blow to China. The outbreak of the second war resulted in the Treaty of Tianjin (Tientsin; 1858), which required further Chinese concessions. When China refused to sign subsequent treaties, Beijing (Peking) was captured and the emperor’s summer palace burned. The overall result of these conflicts was to weaken the Chinese imperial system, greatly expand Western influence in China, and pave the way for such uprisings as the Taiping and Boxer rebellions. See also Canton system; British East India Company; Lin Zexu.

Oporto See Porto

opossum Any of about 66 species (family Didelphidae) of New World, mostly arboreal, nocturnal marsupi¬ als. Highly adaptable and prolific, opossums have changed little in mil¬ lions of years. The North American species, the stout-bodied common, or Virginia, opossum (Didelphis marsupialis), grows to 40 in. (100 cm) long. It is largely white and has an opposable clawless toe on each hind foot; with its long, hairless, pre¬ hensile tail, it resembles a large rat.

Up to 25 grublike, 0.07-oz (2-g) newborns compete for the 13 nipples in the pouch, where the survivors spend four or five weeks; they spend the following eight to nine weeks clinging to the mother’s back. The common opossum may feign death (“play possum”) if surprised. It eats small animals, insects, and fruit, and sometimes domestic poultry and cul¬ tivated grain. See also possum.

Oppenheimer, J(ulius) Rob¬ ert (b. April 22, 1904, New York, N.Y., U.S.—d. Feb. 18, 1967, Prince¬ ton, N.J.) U.S. theoretical physicist. He graduated from Harvard University, did research at Cambridge University, and earned a doctorate from Gottingen University. He returned to the U.S. to teach at the Cali¬ fornia Institute of Technology (1929^47). His research focused on energy processes of subatomic particles, and he trained a generation of Ameri¬ can physicists. In World War II he was named director of the army’s atomic-bomb project, later known as the Manhattan Project, and set up the laboratory in Los Alamos, N.M., that remains a principal weapons- research laboratory. He directed the Institute for Advanced Study in Prince¬ ton (1947-66). He strongly opposed the development of the hydrogen bomb, and in 1953 he was suspended from secret nuclear research as an alleged communist sympathizer and a security risk; the case, which pit¬ ted him against Edward Teller, became a worldwide cause celebre. In 1963 he was reinstated and awarded the Enrico Fermi Award.

opportunity cost In economic terms, the opportunities forgone in the choice of one expenditure over others. For a consumer with a fixed income, the opportunity cost of buying a new dishwasher might be the value of a vacation trip never taken or several suits of clothes unbought.

The concept of opportunity cost allows economists to examine the rela¬ tive monetary values of various goods and services.

opposition, square of Geometrical representation of the traditional logical relations of opposition (contradictories, contraries, subalterns) among the four types of propositions (universal affirmative or A-proposition, universal negative or E, particular affirmative or I, particu¬ lar negative or O) in the Aristotelian doctrine of the syllogism. At the top left is the A; at the top right is the E; below the A is the I; and below the E is the O. The A and the O, like the E and I, are contradictories (diago¬ nal relations); the A and the E are contraries; and the I is subaltern to (hence implied by) the A, the O subaltern to the E. Whereas contradic¬ tories have opposite truth-values (one true, the other false), contraries cannot both be true but can both be false.

optical activity Ability of a substance to rotate the plane of polarization of a beam of light passed through it, either as crystals or in solution. Clock¬ wise rotation as one faces the light source is “positive,” or dextrorotary; counterclockwise rotation “negative,” or levorotary. Louis Pasteur was the first to recognize that molecules with optical activity are stereoisomers (see isomerism). Optical isomers occur in pairs that are nonsuperimposable mirror images of one another. They have the same physical properties except for their effect on polarized light; in chemical properties they differ only in their interactions with other stereoisomers (see asymmetric synthesis).

optical character recognition See OCR optical scanner See optical scanner

optics Science concerned with the production and propagation of light, the changes it undergoes and produces, and closely related phenomena. Physical optics deals with the nature and properties of light; geometric optics deals with the formation of images by mirrors, lenses, and other devices that use light. Optical data processing involves manipulation of the information content of an image formed by coherent (one-wavelength) optical systems. The study of optics has led to the development of devices such as EYEGLASSES and CONTACT LENSeS, TELESCOPES, MICROSCOPES, CAMERAS, BIN¬ OCULARS, lasers, and optical fibres (see fibre optics).

Optimates and Populares \,ap-ti- , ma-tez... 1 pap-y9- , lar-ez\ Ideo¬ logical positions in ancient Rome that became defined in the early 1st century bc. Both groups came from the wealthier classes. The Optimates (Latin: “Best Ones,” “Aristocrats”) promoted the dominance of the Sen¬ ate and the proper balance of the constitution. The Populares (“Dema¬ gogues,” “Populists”) used and defended the powers of the popular assemblies and the office of tribune and advocated such measures as land distribution, debt cancellation, and subsidized grain allowances. Their polarization led to civil wars—notably those between Julius Caesar and Pompey and between Octavian (Augustus) and Mark Antony —and the fall of the republic with Augustus’s accession.

optimization Field of applied mathematics whose principles and meth¬ ods are used to solve quantitative problems in disciplines including phys¬ ics, biology, engineering, and economics. Questions of maximizing or minimizing functions arising in the various disciplines can be solved using the same mathematical tools (see maximum; minimum). In a typical optimi¬ zation problem, the goal is to find the values of controllable factors deter¬ mining the behaviour of a system (e.g., a physical production process, an investment scheme) that maximize productivity or minimize waste. The simplest problems involve functions (systems) of a single variable (input factor) and may be solved with differential calculus. Linear programming was developed to solve optimization problems involving two or more input variables. See also simplex method.

optometry \ap-'ta-ni3-tre\ Profession concerned with examining the eyes for defects or faults of refraction. Optometrists prescribe optical aids (e.g., eyeglasses, contact lenses), supervise eye exercise programs to treat vision problems, and examine the eyes for disorders such as glaucoma and cataracts. They are generally not licensed to prescribe drugs or trained to perform surgery. See also ophthalmology.

opuntia \o-'p3n-sh3\ Any plant of the genus Opuntia, the largest genus of the cactus family. Native to the New World, it has characteristic small bristles with backward-facing barbs. Subgroups are based on the form of the stem segments: chollas have cylindrical joints, while prickly pears have flat joints. Sizes range from tiny, cold-hardy forms to treelike varieties. In the Northern Hemisphere, opuntia is found farther north than any other cactus.

Virginia, or common, opossum (Didel¬ phis virginiana).

ROBERT J. ELUSON-THE NATIONAL AUDUBON SOCIETY COLLECTION/PHOTO RESEARCHERS

© 2006 Encyclopaedia Britannica, Inc.

Opus Dei ► Orbison I 1413

Opus Dei Latin "work of God" Roman Catholic lay and clerical organization whose actions and beliefs have been both criticized and praised. Its members seek personal Christian perfection, strive to imple¬ ment Christian ideals in their chosen occupations, and promote Christian values to society as a whole. Opus Dei, in full Prelature of the Holy Cross and Opus Dei, was founded in 1928 in Spain by Josemarfa Escriva de Balaguer y Alba (canonzied in 2002). It is theologically conservative and accepts the teaching authority of the church without question. It was granted special status as the first and only personal prelature in the church by Pope John Paul II in 1982 and has established numerous vocational schools and universities. It is also highly controversial, accused of secrecy, using cult-like recruiting practices, and having grand political ambitions. There are separate organizations for men and women, which, since 1982, have been headed by a prelate elected by its members. At the beginning of the 21st century priests constituted only a tiny percentage of the orga¬ nization, numbering roughly 1,600 of the nearly 84,000 members living in 80 countries.

oracle Source of a divine communication delivered in response to a petitioner’s request. Ancient Greece and Rome had many oracles. The most famous was that of Apollo at Delphi, where the medium was a woman over 50 called the Pythia. After bathing in the Castalian spring, she appar¬ ently would descend into a basement cell, mount a sacred tripod, and chew the leaves of the laurel, sacred to Apollo. Her utterances, which were often highly ambiguous, were interpreted by priests. Other oracles, including those at Claros (Apollo), Amphicleia (Dionysus), Olympia (Zeus), and Epi- daurus (Asclepius), were consulted through various other methods; for example, the oldest of the oracles, that of Zeus at Dodona, spoke through the whispering of the leaves of a sacred oak. At some shrines, the inquirer would sleep in the holy precinct and receive an answer in a dream.

oral tradition Cultural information passed on from one generation to the next by storytellers. The forms of oral tradition include poetry (often chanted or sung), folktales, and proverbs as well as magical spells, reli¬ gious instruction, and recollections of the past. Music and rhyme com¬ monly serve as both entertainment and aids to memory. Epic poems concerning the destiny of a society or summarizing its myths often begin as oral tradition and are later written down. In oral cultures, oral tradi¬ tion is the only means of communicating knowledge. The prevalence of radio, television, and newspapers in Western culture has led to the decline of oral tradition, though it survives among old people and some minority groups as well as among children, whose games, counting rhymes, and songs are transmitted orally from generation to generation.

Oran \o-'ran\City (pop., 1998: 692,516), northwestern Algeria. Situated on the Mediterranean Sea, it is about midway between Tangier, Morocco, and Algiers. With the adjacent Mers el-Kebir, it is the country’s second largest port. Founded in the 10th century by Andalusians as a base for trade with the northern African hinterland, it was held by the Spanish until 1708, when it fell to the Ottomans. It was devastated by an earthquake in 1790. In 1792 the Ottomans settled a Jewish community there. In 1831 it was occupied by the French, who established a modem port and naval base. In World War II (1939—45) it came under the control of the Allied Powers. Most of its European inhabitants left after Algerian independence in 1962. It is divided into a waterfront and the old and new city sections built on terraces above it.

orange Any of several species of small trees or shrubs in the genus Citrus of the rue (or citrus) family and their fruits. Grown in tropical and subtropical regions, the nearly round fruits have leathery, oily rinds and edible, juicy inner flesh rich in vitamin C. Key commercial species include the China (sweet, or common) orange; the mandarin orange (including tangerines); and seedless navel oranges. The tree has broad, glossy, medium-size evergreen leaves, leafstalks with narrow wings, and very fragrant flowers. It bears fruit abundantly for 50-80 years. Oranges do not improve in quality off the tree, so they are picked when fully ripe. A sizeable portion of the U.S. crop is processed for frozen concentrated juice. By-products include essential oils, pectin, candied peel, orange mar¬ malade, and stock feed.

Orange, house of Princely dynasty and royal family of The Nether¬ lands. The title began with William I (the Silent), prince of Orange-Nassau, who was stadtholder (viceroy) of the Netherlands, as were his descen¬ dants until 1795. In 1815 William VI became William I, king of The Neth¬ erlands. Through his descendants, the male line of the royal dynasty

continued until 1890, when Wilhelmina, daughter of William III, became queen. In 1908 she decreed that her descendants should be styled princes and princesses of Orange-Nassau.

Orange Free State Former province, central South Africa. Before the arrival of the Europeans, the area was the home of Bantu- speaking peoples. Afrikaners came in large part during the Great Trek of the 1830s. Britain administered the territory from 1848 to 1854; then the indepen¬ dent Orange Free State was established. British rule was reimposed fol¬ lowing the South African War in 1902, though self-government was later restored. In 1910 it became the Orange Free State province of the Union of South Africa (from 1961 the Republic of South Africa). After the South African elections of 1994, it became the province of Free State. Blacks make up about 80% of the population; most of the whites speak Afrikaans. The province’s capital is Bloemfontein.

Orange River River, southern Africa. It rises in the Lesotho Highlands as the Sinqu River and flows west as the Orange across South Africa. It passes the southern edge of the Kalahari Desert and winds through the Namib Desert before draining into the Atlantic Ocean in South Africa. It forms the border between South Africa and Namibia. It is about 1,300 mi (2,100 km) long. There are some irrigated sections along the river and many dams but no large towns.

orangutan \d-'raq-9- l tar)\ or orang Species (Pongo pygmaeus , fam¬ ily Hominidae) of arboreal great ape, found only in the lowland swamp forests of Borneo and Sumatra but originally in the tropical forests of South Asia as well. The orangutan (Malaysian for “person of the for¬ est”) has a short thick body, long arms, short legs, and shaggy reddish hair. Males are about 4.5 ft (137 cm) tall and weigh about 185 lb (85 kg); females are smaller. Orangutans are placid, deliberate, ingenious, and persistent. Males have flat, fatty cheekpads and a baglike, pendulous swelling at the throat. Orangutans use all four limbs to walk and climb.

They eat mostly figs and other fruits and some leaves, bark, and insects.

They sleep in trees on a platform built of interwoven branches. Adults are solitary and live far apart, com¬ ing together only for a brief court¬ ship. The mother carries and nurses the single young for almost three years. Though generally silent, the adult male has a loud, roaring “long call.” The orangutan is an endangered species.

Oranjestad Vo-'ran-yo-.statV Seaport and chief administrative town (pop., 2000: 26,355), Aruba, Netherlands Antilles. It is located on the western coast of this Caribbean island. It is a free port and a petroleum¬ processing and shipping centre.

oratorio Large-scale musical composition on a sacred subject for solo voices, chorus, and orchestra. The term derives from the oratories, com¬ munity prayer halls set up by St. Philip Neri in the mid 16th century in a Counter-Reformation attempt to provide locales for religious edification outside the church itself, and the oratorio remained a nonliturgical (and non-Latin) form for moral musical entertainment. The first oratorio, really a religious opera, was written in 1600 by Emilio del Cavaliere, and the ora¬ torio’s development closely followed that of opera. Giacomo Carissimi pro¬ duced an important body of Italian oratorios, and Marc-Antoine Charpentier transferred the oratorio to France in the later 17th century. In Germany the works of Heinrich Schutz anticipate the oratorio-like Passions of Johann Sebastian Bach. The most celebrated oratorio composer was George Frideric Handel; his great English works include the incomparable Messiah (1742). Handel inspired Franz Joseph Haydn’s great Creation (1798) and exerted great influence on the 19th-century oratorio, whose composers include Hector Berlioz, Felix Mendelssohn, and Franz Liszt. Though the oratorio thereafter declined, 20th-century oratorio composers included Edward Elgar, Igor Stravinsky, Arthur Honegger, and Krzysztof Penderecki.

Orbison, Roy (b. April 23, 1936, Vernon, Texas, U.S.—d. Dec. 6, 1988, Hendersonville, Tenn.) U.S. singer and songwriter. He formed his first

© 2006 Encyclopaedia Britannica, Inc.

1414 I orbital ► order

musical group at age 13. His first single, “Ooby Dooby” (1956), was fol¬ lowed in the early 1960s by a string of hits, carefully crafted ballads of loneliness and heartache that included “Only the Lonely,” “I Can’t Stop Loving You,” “Crying,” “In Dreams,” and “Oh, Pretty Woman.” He was known for his soaring voice, one of the most operatic in all rock music. His career waned after the death of his wife in a motorcycle accident (1966) and the death of two sons in a fire (1968). He made a comeback in the 1980s; with Bob Dylan, George Harrison (1943-2001), and Tom Petty (b. 1953) he formed the band the Traveling Wilburys.

orbital Mathematical expression, called a wave function, that describes properties characteristic of no more than two electrons near an atomic nucleus or molecule. An orbital can be considered a three-dimensional region in which there is a 95% probability of finding an electron. Atomic orbitals are designated by a combination of numerals and letters (e.g.. Is, 2 p, 3d, 4 f). The numerals are the principal quantum number and are related to the atomic energy level and distance from the nucleus; the letters indi¬ cate the orbital’s angular momentum and hence its shape. An s orbital with zero net orbital angular momentum is spherical. A p orbital with one fundamental unit of angular momentum, fi, is shaped somewhat like a dumbbell ( fi is Planck’s constant, h, divided by 2k). The shapes of the other orbitals are more complicated. Molecular orbitals have geometries determined by the overlap of two or more atomic orbitals and are desig¬ nated by Greek symbols, e.g., a and n.

orca See killer whale

Orcagna \or-'kan-ya\, Andrea orig. Andrea di Cione (b. c. 1308, Florence?, Republic of Florence—d. c. 1368, Florence) Florentine painter, sculptor, and architect. A goldsmith’s son, he was the leading member of a family of painters and the most prominent Florentine artist of the mid 14th century. His altarpiece for the Strozzi Chapel in Florence’s Santa Maria Novella (1354-57) shows his ability to unify the multiple panels of a polyptych. As a sculptor he is known for a single work: the taber¬ nacle in the guild oratory of Or San Michele (1352-60), a decorative structure of great complexity that is among the finest examples of the expressive art that sprang up in Tuscany after the Black Death. He was employed as architect on Florence’s Duomo (cathedral) in 1357 and

1364-67.

orchestra Instrumental ensemble of varying size and composition. Today the term orchestra usually refers to the traditional large Western ensemble of bowed stringed instruments with brass, woodwind, and percus¬ sion instruments, with several players to each string part. The develop¬ ment of the orchestra coincides with the early history of opera. A major antecedent of the modern orchestra was that of the mid-17th-century French court, especially as employed by Jean-Baptiste Lully; it was domi¬ nated by 24 bowed strings but also often included woodwind instruments. Trumpets, horns, and timpani were often added in the early 18th century p_ and were standard by the time of Franz Joseph Haydn. During the 19th

century there was a considerable expansion, particularly in the number wm and variety of wind and percussion instruments; some works called for

ifl well over 100 musicians. The symphony orchestra changed little in the

20th century. See also orchestration.

brasses

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orchestration Art of choosing which instruments to use for a given piece of music. The sections of the orchestra historically were separate

ensembles: the stringed instruments for indoors, the woodwind instru¬ ments for outdoors, the horns for hunting, and trumpets and drums for battle or royal ceremony. Once entirely dependent on what was available or customary, composers began to explore the musical potential of instru¬ mental combinations with the advent of the modern orchestra in the mid- to late 18th century. The first great orchestration text was written by Hec¬ tor Berlioz in 1844.

orchid Any of the 15,000-35,000 species in 400-800 genera of non- woody perennial plants that make up the family Orchidaceae. Bearing attractive flowers, orchids grow in most of the nonpolar world, espe¬ cially in tropical regions, in soil or on other plants. Hybrids with showy flowers for the commercial trade come from the genera Cattleya,

Cymbidium, Vanda, and Laelia.

Flowers vary widely in size, colour, and shape, but all are bilaterally symmetrical and have three sepals.

Most orchids photosynthesize, but some live on dead organic material or absorb food from a fungus living in their roots. Vanilla is extracted from the seedpod of the genus Vanilla. Many folk medicines, local beverages, and foods are prepared from parts of orchid plants.

orchitis \or-'kI-t9s\ Inflammation and swelling of the testes, caused by infection (most often mumps) or chemical or physical injury. The testicles’ rich blood and lymphatic supply block most infections in the absence of severe injury. Usual symptoms are high fever, sudden pain in the testicle, nausea and vomiting, and swelling, tightness, and tenderness of the gland. Fluids with pus or blood may accumulate in the scrotum, which is gen¬ erally red and thickened. Treatment may include antibiotics, bed rest, support of the testes, compresses, and surgery or drainage.

Orchomenus \6r-'ka-m9-n9s\ Ancient city, northwestern Boeotia, Greece. It was the northernmost fortified town in Mycenaean times and controlled a large part of Boeotia. In c. 550 bc it became one of the first cities to coin money, thereby gaining fame for its wealth. It was frequently attacked and finally destroyed by Thebes in the 4th century bc. Excava¬ tions have revealed that it was an important Neolithic and Bronze Age site, with a beehive temple and palace.

Orczy \'ort-se\, Emmuska (Magdalena Rosalia Marie Josepha Barbara), Baroness (b. Sept. 23, 1865, Tamaors, Hung.—d. Nov. 12, 1947, London, Eng.) Hungarian-born British novel¬ ist. The daughter of a noted musician, she was educated in Brussels and Paris and studied art in London. She became famous as the author of The Scarlet Pimpernel (1905), a swashbuckling adventure set in the era of the French Revolution. Her sequels did not match its great popular success. She also wrote detective stories.

Ord River River, northeastern Western Australia. The Ord rises in the Albert Edward Range and flows east and north to the Cambridge Gulf; it is about 200 mi (320 km) long. Discovered in 1879 by Alexander For¬ rest, it was named for Harry Ord, governor of Western Australia. The Ord River Project is designed to prevent flooding and collect irrigation water.

ordeal In customary law, a test of guilt or innocence in which the accused undergoes dangerous or painful tests believed to be under super¬ natural control. Ordeals by fire or water are the most common. Bums suf¬ fered while passing through fire (as in Hindu custom) or rejection (i.e., being buoyed up) by a body of water (as in witch trials) would be regarded as proof of guilt. In ordeal by combat, as in the medieval duel, the victor is said to win not by his own strength but because supernatural powers have intervened on the side of the right.

order In Classical architecture, any of several styles defined by the par¬ ticular type of column, base, capital, and entablature they use. There are five major orders: Doric, Ionic, and Corinthian (all developed in Greece), and Tuscan and Composite (developed in Rome). The form of the capital is an order’s most distinguishing characteristic. Both the Doric and Ionic orders originated in wooden temples. The Doric is squat and simple. The Ionic, distinguished by the scrolls, or volutes, on its capital, resembles a

Orchid (Polystachya bella).

SVEN SAMEUUS

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order in council ► Orff I 1415

capital I. The Corinthian capital is more ornate, with carved acanthus leaves and scrolls. The Romans modified the Greek orders to produce the Tuscan (a simplified form of the Doric) and Composite (a combination of the Ionic and Corinthian) orders. See also colossal order.

Tuscan

Corinthian

nnnnnnn

Composite

Capital styles for the five major orders of Classical architecture.

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order in council In Britain, a regulation traditionally issued by the sovereign on the advice of the Privy Council. In modern practice, an order is issued only on the advice of ministers, and the minister in charge of the department concerned with the order’s subject matter is responsible to Parliament for its contents. Most orders in council today are issued to implement legislation passed by Parliament.

Order of the Garter See Order of the Garter

ordinary differential equation Equation containing derivatives of a function of a single variable. Its order is the order of the highest deriva¬ tive it contains (e.g., a first-order differential equation involves only the first derivative of the function). Because the derivative is a rate of change, such an equation states how a function changes but does not specify the function itself. Given sufficient initial conditions, however, such as a spe¬ cific function value, the function can be found by various methods, most based on integration.

Ordovician X.or-ds-'vi-shonN Period Interval of geologic time, 490- 443 million years ago, the second oldest period of the Paleozoic Era. It follows the Cambrian and precedes the Silurian. During the Ordovician, many of the landmasses were aligned in the tropics. Life was dominated by marine invertebrates, but some forms of land plants may have appeared during the middle of the period. Spores suggesting a tropical terrestrial environment have been found in rocks of that age.

Ordzhonikidze Nor-jan-yik-'yed-zoX, Grigory (Konstantino¬ vich) (b. Oct. 24,1886, Goresha, Russia—d. Feb. 18,1937, Moscow, Rus¬ sia, U.S.S.R.) Russian communist leader. After the Russian Revolution of 1917, he became chairman of the Caucasian bureau (1921) and helped the Red Army conquer Georgia, forcing its merger with Armenia and Azer¬ baijan into the Transcaucasian Federal Republic and then into the Soviet Union. He became a member of the Politburo (1930) and commissar for heavy industry (1932), but in the mid-1930s he opposed Joseph Stalin’s industrial policy. His sudden death was ascribed to natural causes, but Nikita Khrushchev later charged (1956) that Stalin had driven him to suicide.

ore Aggregate of economically important minerals that is sufficiently rich to separate for a profit. Although more than 3,500 mineral species are

known, only about 100 are considered ore minerals. The term originally applied only to metallic minerals (see native element) but now includes such nonmetallic substances as sulfur, calcium fluoride (fluorite), and barium sulfate (barite). Ore is always mixed with unwanted rocks and minerals, known collectively as gangue. The ore and the gangue are mined together and then separated. The desired element is then extracted from the ore. The metal may be still further refined (purified) or alloyed with other metals.

oregano Flavourful dried leaves and flowering tops of any of various perennial herbs of the MINT family, particularly Origanum vulgare. Oregano is an essential ingredient of Mediterranean cuisines; in the U.S., use of oregano rose sharply in the late 20th century, largely because of the popularity of pizza. Native to the Mediterranean and western Asia, the herbs are now naturalized in parts of Mexico and the U.S.

Oregon State (pop., 2000: 3,421,399), U.S., northwestern region. Lying on the Pacific Ocean, it is bordered by Washington, Idaho, Nevada, and California. It covers 97,073 sq mi (251,419 sq km). Its capital is Salem. The Columbia River forms its northern boundary; the Snake River is its upper eastern boundary. The Cascades Range, with Mount Hood, is in western central Oregon. First sighted by Spanish explorers, it was visited by Fran¬ cis Drake in 1579 and by James Cook in 1778. The area was inhabited by many American Indian peoples when in 1792 Capt. Robert Gray explored the Columbia River, giving the U.S. a claim to the region. The river’s mouth was reached by the Lewis and Clark Expedition in 1805. The first white settlement was founded at Astoria in 1811 by the fur trader John J. Astor. Settlement of the area accelerated from c. 1843 with mass migration over the Oregon Trail. It was part of the Oregon Territory and was admitted to the Union as the 33rd state in 1859. The state’s economy is dependent on its forests, farms, and livestock. Salmon and shellfish are the bases of the fishing industry. Centres of population, arts, and education are Portland, Eugene, and Medford.

Oregon Caves National Monument National monument, south¬ western Oregon, U.S. It is a single cave comprising a series of chambers joined by subterranean corridors on four levels. Located in the Siskiyou Mountains near the California border, the monument was established in 1909. It has an area of 488 acres (197 hectares). It contains many stalag¬ mites, stalactites, and other formations.

Oregon Question Dispute over ownership of the Pacific Northwest region of North America. Spain, Russia, the U.S., and Britain all had claims to the region based on exploration or settlement. Spain vacated its claims after the Nootka Sound controversy and in an 1819 treaty with the U.S. The U.S. and Britain established a joint claim over the Oregon Coun¬ try in 1818. Russia abandoned its claims in separate treaties (1824-25). A compromise Oregon Treaty between the U.S. and Britain (1846) drew the U.S.-Canada land boundary at 49°N.

Oregon Trail Major U.S. route to the Northwest in the 19th century. It stretched about 2,000 mi (3,200 km), from Independence, Mo., to the Columbia River region of Oregon. First used by fur traders and mission¬ aries, it was heavily used in the 1840s by travelers to Oregon, including settlers of the “great migration,” led by Marcus Whitman. Of all western trails, it was in use for the longest period, surviving competition from the railroad by serving as a trail for eastward cattle and sheep drives.

Orestes \o-'res-tez\ In Greek mythology, the son of Agamemnon and Clytemnestra. According to Homer, Orestes was away when his father returned from Troy to meet his death at the hands of Aegisthus, his wife’s lover. On reaching manhood, Orestes avenged his father by killing Aegis¬ thus and Clytemnestra. Aeschylus’s dramatic trilogy the Oresteia recounts the murder and the pursuit of Orestes by the Furies for the crime of matri¬ cide. In Euripides’ Iphigeneia in Tauris, Orestes is reunited with his sister Iphigeneia and regains his father’s kingdom.

Oresund Vce-ro-.sonV Almost tideless strait between SjalLLAND island, Denmark, and Skane, Sweden, connecting the Kattegat Strait with the Baltic Sea. It is one of the busiest sea lanes in the world, though ice some¬ times impedes navigation in severe winters. Three large islands within it divide the waters into channels. The strait’s principal ports are Copen¬ hagen and Helsing0r in Denmark and Malmo and Halsingborg in Sweden.

Orff, Carl (b. July 10, 1895, Munich, Ger.—d. March 29,1982, Munich) German composer and music educator. He trained at the Munich Acad¬ emy and held several musical posts thereafter. In the 1920s he grew inter¬ ested in early Baroque music and the association of music with movement.

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1416 I organ ► Orient Express

In 1924 he cofounded a school for which he devised a comprehensive music education program (Orff Schulwerk) involving improvisation on specially designed gamelan-like percussion instruments; the program has since come into wide international use. He typically used repetitive rhythms, bare harmonies, and powerfully direct vocal parts, as in his best- known work, the secular oratorio Carmina Burana (1937), which is based on a manuscript of medieval poems.

organ Keyboard instrument in which pressurized air produces notes by means of a series of tuned pipes. The simplest organs consist of a single rank of pipes, each corresponding to a single key. They are arranged over a wind chest connected to the keys by a set of valves and fed with a sup¬ ply of air by electrically or mechani¬ cally activated bellows. By pulling out knobs, called stops, the player engages new ranks of pipes. Two dis¬ tinct types of pipes are used: flue pipes (both open and stopped) pro¬ duce sound by directing air against the edge of an opening in the pipe, whereas reed pipes sound by means of a thin metal tongue inside the pipe that vibrates against a fixed projec¬ tion next to it. A large organ may have five or more banked keyboards, or manuals, each of which controls a distinctive group of pipes. Most organs also have pedalboards played with the feet. A large organ’s pipes may vary in length from about 1 in. to 32 ft (2.5 cm to 10 m), resulting in a huge nine-octave range. The earliest organ (c. 250 bc) was the Greek hydraulis, in which the wind was regulated by water pressure. The bellows-fed organ appeared about the 7th century ad. The organ became firmly associated with the church by the 10th century. As organs became widespread, different regions pursued different modes of construction and sought different tonal ideals. The Baroque German organ is ideally suited to polyphony, while the French taste for variety of timbres eventuated in Aristide Cavaille-Coll’s vast “orchestral” organs. See also harmonium.

Organ Pipe Cactus National Monument National monument, southwestern Arizona, U.S., at the Mexican border. It was established in 1937. With an area of 330,689 acres (133,929 hectares), it preserves seg¬ ments of the mountainous Sonoran Desert and is named for the organ- pipe cactus. Wildlife includes Gila monsters, antelope, coyotes, and a variety of birds.

organic compound Substance whose molecules contain one or more (often many more) carbon atoms (excluding carbonates, cyanides, car¬ bides, and a few others; see inorganic compound). Until 1828 (see urea), scientists believed that organic compounds could be formed only by life processes (hence the name). Since carbon has a far greater tendency to form molecular chains and rings than do other elements, its compounds are vastly more numerous (many millions have been described) than all others known. Living organisms consist mostly of water and organic com¬ pounds: PROTEINS, CARBOHYDRATES, FATS, NUCLEIC ACIDS, HORMONES, VITAMINS, and a host of others. Natural and synthetic fibres and most fuels, drugs, and plastics are organic. Hydrocarbons contain only carbon and hydrogen; organic compounds with other functional groups include carboxylic acids, alcohols, aldehydes, ketones, phenols, ethers, esters, and other, more com¬ plex, molecules, including heterocyclic compounds, isoprenoids, and amino

ACIDS.

organic farming or organic gardening System of crop cultiva¬ tion that uses biological methods of fertilization and pest control as sub¬ stitutes for chemical fertilizers and pesticides, which are regarded by supporters of organic methods as harmful to health and the environment and unnecessary for successful cultivation. It was initiated as a conscious rejection of modern agri-chemical techniques in the 1930s by the British agronomist Sir Albert Howard. Miscellaneous organic materials, includ¬ ing animal manure, compost, grass turf, straw, and other crop residues, are applied to fields to improve both soil structure and moisture-holding capacity and to nourish soil life, which in turn nourishes plants. (Chemi¬ cal fertilizers, by contrast, feed plants directly.) Biological pest control is achieved through preventive methods, including diversified farming, crop rotation, the planting of pest-deterrent species, and the use of integrated

pest management techniques. Bioengineered strains are avoided. Since organic farming is time-consuming, organically grown produce tends to be expensive. Organic produce formerly accounted for a minuscule por¬ tion of total American farm output, but it has seen a huge proportional increase in sales in recent years.

Organization for Economic Cooperation and Develop¬ ment See Organization for Economic Cooperation and Development

Organization of African Unity (OAU) See African Union

Organization of American States (OAS) International organiza¬ tion formed in 1948 to replace the Pan-American Union. It promotes eco¬ nomic, military, and cultural cooperation among its members, which include almost all the independent states of the Western Hemisphere. (Cuba’s membership was suspended in 1962.) The OAS’s main goals are to maintain peace in the Western Hemisphere and to prevent intervention in the region by any outside state. Since the end of the Cold War in the early 1990s, the OAS has more actively encouraged democratic government in member states, in part by organizing missions to observe and monitor elec¬ tions. See also Alliance for Progress; Inter-American Development Bank.

Organization of Petroleum Exporting Countries See OPEC organizational psychology See industrial psychology organizational relations See industrial relations

organized crime Crime committed on a national or international scale by a criminal association; also, the associations themselves. Such asso¬ ciations engage in offenses such as cargo theft, fraud, robbery, kidnapping for ransom, and the demanding of “protection” payments. Their princi¬ pal source of income derives from the supply of illegal goods and ser¬ vices for which there is continuous public demand, such as drugs, prostitution, “loan-sharking” (i.e., the lending of money at extremely high interest rates), and gambling. They are characterized by a hierarchy of ranks with assigned responsibilities; the coordination of activities among subgroups; the division of geographic territory among different associa¬ tions; a commitment to total secrecy; efforts to corrupt law-enforcement authorities; and the use of extreme violence, including murder, against rival associations, informers, and other enemies. International rings of smugglers, jewel thieves, and drug traffickers have existed throughout Europe and Asia, and Sicily and Japan have centuries-old criminal orga¬ nizations. In the U.S., organized crime flourished in the 20th century, especially during the Prohibition era. In the late 20th and early 21st cen¬ turies, it became immensely powerful in Russia, taking advantage of a weak and impoverished government and widespread official corruption. See also Mafia; yakuza.

organum Vor-go-nsnA Early polyphonic setting of plainchant (see Gre¬ gorian chant), the earliest form of counterpoint. The oldest written organum (c. 900), which evidently reflects a prevailing improvisational practice, consists of two lines moving simultaneously, note against note, the added line often paralleling the chant line a fourth or a fifth below. Later the added line acquired greater melodic individuality and indepen¬ dence. Organum consisting of more than one note against each chant note (florid or melismatic organum) appeared by the early 12th century. Three- and four-voice organum were first composed by the Notre-Dame school. Organum died out with the advent of the 13th-century motet.

Orhon River or Orkhon \'6r-,k6n\ River River, north-central Mon¬ golia. Some 700 mi (1,130 km) long, it rises from the slopes of the Han- gayn Mountains and flows east, then north past the ruins of Karakorum. The 8th-century funerary stelae discovered in the river’s valley in 1889 contain some of the oldest known Turkic writing, called the Orhon inscrip¬ tions. The river is navigable for shallow-draft vessels only in July and August.

oriel Bay window in an upper story, supported from below by project¬ ing corbels. Usually semihexagonal or rectangular in plan, oriels first became prevalent early in the 15th century. They were often placed over gateways or entrances to manor houses and public buildings of the late Gothic and Tudor periods. In cities of North Africa and the Middle East, the moucharaby is an oriel that uses grills or lattices in place of glass and shutters. See also brise-soleil.

Orient Express Luxury train that ran from Paris to Constantinople (Istanbul) for over 80 years (1883-1977). Developed by the Belgian busi¬ nessman Georges Nagelmackers, its luxuriously furnished cars became

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The Bruckner Organ, 18th century; in the church of the Abbey of Sankt Flo- rian, Austria

TONI SCHNEIDERS

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orientation ► Orleans I 1417

the symbol of glamour for European society. Europe’s first transcontinen¬ tal express train, it covered over 1,700 mi (2,740 km); after 1919 the route extended from Calais and Paris to Lausanne and via the Simplon Pass to Milan, Venice, Zagreb, and beyond. Service was suspended during both world wars. Discontinued in 1977, it was revived in 1982 to run between London and Venice as the “Venice Simplon Orient Express.”

orientation In architecture, the position of a building on its site. In Mesopotamia and Egypt, as well as in pre-Columbian Central America, a building’s important features, such as entrances and passages, faced the rising sun. Mosques are oriented so that the mihrab faces Mecca. Chris¬ tian churches have usually been oriented with the apse or altar at the east¬ ern end. Orientation is frequently planned to take maximum advantage of daily and seasonal variations of sunlight. A structure’s optimal orientation is usually a compromise between its function, location, and the prevail¬ ing environmental factors of solar radiation, light, humidity, and wind that make up the site’s microclimate.

orienteering Cross-country footrace in which each participant uses a map and compass to navigate between checkpoints along an unfamiliar course. Introduced in Sweden in 1918, it later spread throughout Europe. World championships have been held since 1966. Runners set out at inter¬ vals; the winner is the runner who completes the course in the fastest time. Orienteering is also practiced by cyclists, canoeists, horseback riders, and skiers.

origami See paper folding

Origen Vor-i-jonX orig. Oregenes Adamantius (b. c. 185, prob¬ ably Alexandria, Egypt—d. c. 254, Tyre, Phoenicia) Greek theologian, one of the Fathers of the Church. Probably the son of a Christian martyr, Origen studied philosophy in Alexandria and served as head of its cate¬ chetical school for 20 years. He later settled in Palestine and founded a school of philosophy and theology. He traveled widely as a preacher; he was imprisoned and tortured during the persecutions of the emperor Decius in 250 but survived to die several years later. His greatest work, the Hexapla, is a synopsis of six versions of the Hebrew scriptures. His writ¬ ings, influenced by Neoplatonism and Stoicism, stress that providence seeks to restore all souls to their original blessedness and emphasize the cen¬ trality of the Word (Logos) in the cosmos. He held that even Satan was not beyond repentance and salvation, a view for which he was condemned. Although attacked as a heretic, Origen remained an influential thinker throughout late antiquity and the Middle Ages.

original sin In Christian doctrine, the condition or state of sin into which each human being is bom, or its origin in Adam’s disobedience to God when he ate the fruit of the tree of knowledge of good and evil. His guilt was transmitted to his descendants. Though Genesis describes Adam’s sufferings as the consequence of his disobedience, it does not make Adam’s sin hereditary. The main scriptural basis of the doctrine is found in the writings of St. Paul; St. Augustine helped make humanity’s sinful nature a central element in orthodox Christian theology. Medieval theologians continued to explore the issue, and Thomas Aquinas offered a more optimistic view of human nature in his teachings on original sin than had Augustine. Martin Luther and John Calvin accepted a more Augus- tinian understanding, and modern evolutionary theory and biblical source criticism raised new challenges for the definition of original sin.

Orinoco X.or-e-'no-koX River Major river, South America. It rises on the western slopes of the Parima Mountains along the border between Venezu¬ ela and Brazil. It flows in a giant arc through Venezuela for about 1,700 mi (2,740 km) and enters the Atlantic Ocean near the island of Trinidad. It forms part of the border between Colombia and Venezuela. With its tribu¬ taries, it is the northernmost of South America’s four major river systems. The aquatic fauna include the piranhas and the Orinoco crocodile. The river basin is largely inhabited by indigenous Indian groups.

oriole Any songbird of 24 species in the Old World genus Oriolus (fam¬ ily Oriolidae) or 30 species in the New World genus Icterus (family Ict- eridae). Males typically are black and yellow or black and orange, with some white. Females are less colourful. Orioles are not easily seen but may be detected by their loud whistling and jarring notes. All are insect eaters (several species also eat fruit) in woodlands and gardens, chiefly in warm regions. The only European species is the 9.5-in. (24-cm) golden oriole ( O . oriolus). Other Oriolus species are found in Africa, Asia, and Australia. The Baltimore oriole (/. galbula) breeds in North America east of the Rocky Mountains. See photograph above.

Orion Xo-'ri-onX In Greek mythology, a powerful hunter. He was some¬ times said to be the son of Poseidon. He drove the wild beasts out of the island of Chios and fell in love with Merope, daughter of the island’s king. Disapproving of Orion, the king had him blinded, but his vision was restored by the rays of the rising sun. He later went to Crete to live and hunt with Artemis. Some legends hold that he was killed by Artemis or Apollo out of jealousy; another tells that he was fatally bitten by a scor¬ pion. After his death the gods placed him in the sky as a constellation.

Orion Xo-'rl-onX Nebula Bright nebula, faintly visible to the unaided eye in the sword of the hunter’s figure in the constellation Orion. About 1,500 light-years from Earth, it contains hundreds of very hot young stars clustered about a group of four massive stars known as the Trapezium. Radiation primarily from these four stars excites the nebula to glow. Dis¬ covered in the early 17th century, it was the first nebula to be photo¬ graphed (1880).

Orissa State (pop., 2001 prelim: 36,706,920), eastern India. It lies on the Bay of Bengal and is bordered by Andhra Pradesh, Chhattisgarh, Jhark¬ hand, and West Bengal states. It occupies an area of 60,119 sq mi (155,707 sq km), and its capital is Bhubaneshwar; Cuttack is the largest city. Part of the ancient kingdom of Kalinga, it was a stronghold of Hinduism before its conquest by the Afghan rulers of Bengal in 1568, when it became part of the Mughal Empire. It was ruled by Britain from 1803 until India’s independence in 1947 and became a state in 1950. Situated in a tropical savanna that is subject to cyclones, it has a largely rural population, which is engaged mainly in agriculture. Crops include rice, oilseed, jute, and sugarcane. It has a rich artistic heritage and contains some of the best examples of Indian art and architecture.

Orizaba See Citlaltepetl Orkhon River See Orhon River

Orkney Islands Island group (pop., 2001: 19,245), Scotland. Lying north of the Scottish mainland, it comprises more than 70 islands and islets and constitutes the Orkney council area. The Orkney Islands, only 20 of which are inhabited, were the Orcades of ancient Classical literature. There is much evidence of prehistoric inhabitants. Norse raiders arrived in the late 8th century ad and colonized the islands in the 9th century. Thereafter they were ruled by Norway and Denmark until Scotland annexed them in 1472. It is a prosperous agricultural area. Kirkwall is the administrative seat.

Orlando City (pop., 2000: 185,951), central Florida, U.S. Settlement began c. 1844 around an army post. It was renamed in 1857 to honour Orlando Reeves, an army sentry killed during the Seminole Wars. After 1950 the development of the aerospace complex at Cape Canaveral and, after 1971, of nearby Disney World boosted the city’s population and economy. It is also the centre of a citrus farming region.

Orlando, Vittorio Emanuele (b. May 19, 1860, Palermo, Italy—d. Dec. 1, 1952, Rome) Italian politician and prime minister (1917-19). He was elected to Italy’s Chamber of Deputies in 1897 and served in cabi¬ net positions from 1903. As prime minister, he led Italy’s delegation to the Paris Peace Conference, but he was unable to obtain concessions from the Allies for Italian-claimed territory and resigned. As president of the Chamber of Deputies (1919-25), he resigned in protest against the elec¬ toral fraud of Benito Mussolini’s Fascist Party. He was president of the postwar Constituent Assembly (1946^-7).

Orleans \or-la-'a n \ ancient Aurelianum City (pop., 1999: 113,126), capital of the Centre region , north-central France. It was conquered by Julius Caesar in 52 bc and became an intellectual centre under Charle¬ magne. It was a major cultural centre in the Middle Ages and became a royal duchy under Philip VI in 1344. During the Hundred Years' War, the English siege in 1429 was relieved by Joan of Arc, known as the Maid of Orleans, and her troops. Located on the Loire River in a fertile valley, it is important for market gardening, horticulture, and textile production.

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1418 I Orleans ► Oromo

Orleans, house of Name of the cadet or junior branch of the Valois and Bourbon houses of France. Of the four dynasties of princes, Philippe I (1336-75) died without an hem Descendants of the second dynasty, headed by Louis I (1372-1407), held the title until 1545. The third dynasty was headed by Gaston (1608-60), whose title from 1626 passed to the fourth dynasty under Philippe I (1640-1701), younger brother of Louis XIV. Philippe’s descendants included Louis-Philippe-Joseph, duke d' Orleans, and Louis-Philippe, king of France from 1830 to 1848.

Orleans, Louis-Philippe-Joseph, duke d' known as Philippe Egalite (b. April 13, 1747, Saint-Cloud, France—d. Nov. 6, 1793, Paris) French Bourbon prince who supported popular democracy in the French Revolution. A cousin of Louis XVI, he disapproved of Marie-Antoinette and lived away from the royal court at Versailles. In 1787 he was exiled to his estates for challenging the king’s authority. In 1789 he was elected to the Estates General and soon joined the Third Estate. After joining the Jacobin Club (1791), he renounced his title of nobility (1792) and accepted the name Philippe Egalite from the Paris Commune. In the National Con¬ vention, he supported the radicals, but, after his son Louis-Philippe defected to the Austrians, he was accused of conspiracy, arrested, and guillotined.

Orlov Vsr-'loA, Aleksey (Grigoryevich), Count (b. Oct. 5, 1737, Lyutkino, Tver province, Russia—d. Jan. 5, 1808, Moscow) Russian mili¬ tary officer. He became an officer in the Russian guards and adviser to his brother Count Grigory G. Orlov, with whom he planned the overthrow of Peter III (1762) and the installation of Catherine II as empress. Promoted to major general, he was given command of the Russian fleet in the Russo-Turkish War.

Orlov, Grigory (Grigoryevich), Count (b. Oct. 17, 1734, Lyut¬ kino, Tver Province, Russia—d. April 24, 1783, Neskuchnoye, near Mos¬ cow) Russian military officer and lover of Catherine II. An artillery officer, he fought in the Seven Years' War. While stationed in St. Petersburg, he met the grand duke Peter (later Peter III) and his wife, Catherine, whose lover Orlov became c. 1760. After Peter ascended the throne (1762), Orlov and his brother, Count Aleksey Orlov, planned the coup d'etat that over¬ threw Peter and made Catherine empress of Russia. As Catherine’s close adviser, he proposed agrarian reforms to help the serfs, but little was accomplished. He lost favour at court c. 1772.

Ormandy, Eugene orig. Jeno Ormandy Blau (b. Nov. 18, 1899, Budapest, Austria-Hungary—d. March 12, 1985, Philadelphia, Pa., U.S.) Hungarian-born U.S. conductor. A violin prodigy, he became professor of violin at the Budapest Royal Academy at age 17. In 1921 he went to New York City, where he played in and conducted a theatre orchestra; he gained national prominence as conductor of the Minneapolis Symphony Orches¬ tra (1931-36). He shared conductorship of the Philadelphia Orchestra with Leopold Stokowski for two years before becoming sole conductor in 1938, and he led the orchestra until he was made laureate in 1980. Ormandy shaped the orchestra’s sound by developing the lush, velvety string colour that became its trademark, and the orchestra made scores of recordings under him.

ormolu Vor-mo-.liA (from French dorure d’or moulu, “gilding with gold paste”) Gold-coloured alloy made up of copper, zinc, and sometimes tin in various proportions but usually at least 50% copper. It is used in mounts (ornaments on borders, edges, and as angle guards) for furniture and for other decorative purposes. After the molten alloy has been poured into a mold and allowed to cool, it is gilded with powdered gold mixed with mercury. It is then fired at a temperature that evaporates the mercury, leaving a gold surface. Ormolu was first produced in France in the mid- nth century, and France remained its main centre of production. See photograph opposite.

Ormonde, James Butler, 12th earl and 1st duke of (b. Oct. 19, 1610, London, Eng.—d. July 21, 1688, Kingston Lacy, Dorset) Anglo- Irish statesman. Born into the prominent Butler family of Ireland, he suc¬ ceeded to the earldom of Ormonde in 1632. In service to the English crown in Ireland from 1633, he fought against the Catholic rebellion from 1641. He concluded a peace with the Catholic confederacy in 1649, then rallied support for Charles II, but he was forced to flee when Oliver Crom¬ well landed at Dublin. He was Charles’s adviser in exile (1650-60). After the Restoration he was appointed lord lieutenant of Ireland (1662-69, 1677-84), where he encouraged Irish commerce and industry. He was created a duke in 1682.

Ormuz See Hormuz

ornamentation In music, the addition of notes for expressive and aesthetic purposes. For example, a long note may be ornamented by rep¬ etition or by alternation with a neighboring note (“trill”); a skip to a non- adjacent note can be filled in with the intervening notes; or the resolution of a dissonance (see consonance and dissonance), because of its inevita¬ bility, can be delayed.

ornamentation In architecture, applied embellishment in various styles that is a distinguishing characteristic of buildings, furniture, and household items. Ornamentation often occurs on entablatures, columns, the tops of buildings, and around entryways and windows, especially in the form of moldings. Throughout antiquity and into the Renaissance, and later for religious buildings, applied ornament was very important, often having symbolic meaning. The anthemion petal motif was especially popular on the moldings of ancient Greek cornices. Other motifs from antiquity include the Egyptian cartouche (oval), fretwork (banding) of capitals, fluting and reeding of columns, bas-relief egg-and-dart moldings (with alternating oval and pointed forms), and scrollwork such as that found on Ionic capitals and in the running-dog pattern (or wave scroll). Brattishing refers to the continuous embellishment around the top of a wall, common in the Gothic period. The diaper motif, an allover pattern of small repeated shapes, was also often used in this period. The use of strapwork (interlaced scrollwork), which originated with Islamic metal¬ work, is characteristic of Mannerist architecture and furniture.

Orne V6m\ River River, northwestern France. It is 94 mi (152 km) long and flows through the Orne and Calvados departments past Caen into the English Channel. Its bridges were seized by the Allied forces during the World War II Normandy Campaign in June 1944.

ornithischian V.or-no-'this-ke-snV Any of the “bird-hipped” dinosaur species (order Omithischia), herbivores with hip bones arranged like those of modern birds, with the pubis bone pointed backward. Many species had a toothless, horny beak and powerful cheek teeth. Omithischians flourished from the Late Triassic to the Late Cretaceous Epoch (227-65 million years ago). Many species (in the suborder Cerapoda) were bipe¬ dal and had ornate skull structures. Some were quadrupedal, with a mas¬ sive head culminating in a great bony frill. Other quadrupeds (in the suborder Thyreophora) had small heads and were heavily plated and armoured along the back, and some had armour on the flanks and head as well. See also protoceratops; saurischian; stegosaur; triceratops.

ornithology Branch of zoology dealing with the study of birds. Early writings on birds were largely anecdotal (including folklore) or practical (e.g., treatises on falconry and game-bird management). From the mid- 18th century on, ornithology progressed from the description and classi¬ fication of new species discovered in scientific expeditions to the examination of internal anatomy to the study of bird ecology and ethology. Ornithology is one of the few scientific fields in which nonprofessionals make substantial contributions; the field observations of birders provide

valuable information on behaviour, ecology, distribution, and migration. Other information is gained by means of radar, radio transmitters, portable audio equipment, and bird banding, which provides information on longevity and movements.

orogeny \6-'ra-jo-ne\ Mountain¬ building event, generally one that occurs in a geosyncline. Orogeny tends to occur during a relatively short geologic time frame. It is usu¬ ally accompanied by folding and faulting of strata and by the deposi¬ tion of sediments in areas adjacent to the orogenic belt. Orogenies may result from continental collisions, the underthrusting of continents by oce¬ anic plates, the overriding of oceanic ridges by continents, and other causes. See also Acadian orogeny, Alleghenian orogeny, Alpine orogeny, Laramide orogeny, Taconic orogeny.

Oromo \6-'ro-mo\ pejorative Galla Major ethnic group of Ethio-

Secretary decorated with ormolu mounts, marquetry, and intarsia, French, c. 1770; in the Wallace Collec¬ tion, London

COURTESY OF TRUSTEES OF THE WALLACE COLLECTION, LONDON

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Orontes River ► orthogonality I 1419

pia, numbering more than 20 million, or nearly one-third of the popula¬ tion, and occupying much of its central and south-central regions. They speak a Cushitic language of the Afroasiatic family. They are a diverse group, having assimilated and intermarried with other peoples since the 16th century. Traditionally the Oromo were nomadic herders, but today most are settled agriculturalists. Politically they are largely subjugated to the dominant Amhara. In religion they are divided among Islam, the Ethio¬ pian Orthodox faith, and traditional beliefs.

Orontes \o-'ran-tez\ River River, Middle East. Rising in the Biqa c Val¬ ley of Lebanon and flowing north between the Lebanon and Anti-Lebanon mountains, it passes the cities of Hims and Hamah in Syria, where it has been dammed to form Hims Lake. Northwest of Hamah it enters Turkey, where it flows west past the ancient city of Antioch and empties into the Mediterranean Sea. It is unnavigable for most of its 355 mi (571 km) length but is an important source of water for irrigation.

Orozco Vo-'ros-koV Jose Clemente (b. Nov. 23, 1883, Ciudad Guzman, Mex.—d. Sept. 7, 1949, Mexico City) Mexican mural painter. When he lost his left hand at 17, he abandoned architectural studies for painting, pursuing Mexican themes. As a caricaturist for a revolutionary paper, he explored Mexico City’s slums and painted a series of waterco¬ lours, House of Tears, on the lives of prostitutes. The reaction of moral¬ ists forced him to flee to the U.S. in 1917, but in 1919 the new government of Alvaro Obregon welcomed him back, and he joined Diego Rivera and David Alfaro Siqueiros in creating large-scale murals for public buildings, in which he continued his radical social commentary. Again forced to abandon Mexico in 1927, he worked until 1934 in the U.S., where his style evolved and matured in murals from coast to coast. In 1934, his international reputation firmly established, he returned to Mexico and embarked on his most technically impressive and emotionally expressive murals, including Catharsis (1934), in the Palacio de Bellas Artes. He was a leader among those who raised Mexican art to a position of inter¬ national eminence.

Orpheus Greek legendary hero who sang and played the lyre so beauti¬ fully that animals, trees, and rocks danced around him. When his wife, Eurydice, was killed by a snake, he went to the underworld in search of her, and his music and grief so moved Hades that he agreed to let Orpheus take Eurydice back to the land of the living on the condition that neither of them look back as they left. On seeing the Sun, Orpheus turned to share his delight with Eurydice, and she disappeared. Orpheus was later torn to pieces by maenads, and his head, still singing, floated to Lesbos, where an oracle of Orpheus was established. By the 5th century bc, a Hellenistic mys¬ tery religion (the Orphic mysteries), based on Orpheus’s songs and teach¬ ings, had arisen. His story became the subject of some of the earliest operas.

Orphic mysteries See mystery religions

Orphism Trend in Cubism that gave priority to colour. Its name, bestowed in 1912 by Guillaume Apollinaire, recalls not only the legendary Orpheus but the Symbolist painters’ description of Paul Gauguin’s use of colour as “Orphic art.” Among the painters who worked in this style were Robert Delaunay, Fernand Leger, Francis Picabia, and Marcel Duchamp. The best-known example is Delaunay’s abstract Simultaneous Composition: Sun Disks (1912-13), in which superimposed circles of colour have their own rhythm and movement.

Orr, Bobby in full Robert Gordon Orr (b. March 20, 1948, Parry Sound, Ont., Can.) Canadian-born U.S. ice-hockey player. He was signed to a junior amateur contract by Boston Bruins scouts when he was 12. He joined the Bruins in 1966 and played with them for 10 seasons, helping them to the playoffs in eight consecutive seasons and to two Stan¬ ley Cup victories (1970, 1972). The first defenseman to lead the National Hockey League in scoring (1970,

1975), he is the only player ever rec¬ ognized as the most valuable defen¬ seman eight years in a row (1967-68 to 1974-75).

Orsted Voer-stodV Hans Christian (b. Aug. 14, 1777, Rudkpbing, Den.—d. March 9, 1851, Copenhagen) Danish physicist and chemist. In

1820 he discovered that electric current in a wire can deflect a magne¬ tized compass needle, a phenomenon that inspired the development of electromagnetic theory. His 1820 discovery of piperine, one of the pun¬ gent components of pepper, was an important contribution to chemistry, as was his preparation of metallic aluminum in 1825. In 1824 he founded a society devoted to the spread of scientific knowledge among the gen¬ eral public. In 1932 the oersted was adopted as the physical unit of mag¬ netic field strength.

Ortega \or-'ta-go\ (Saavedra), (Jose) Daniel (b. Nov. 11, 1945, La Libertad, Nic.) President of Nicaragua (1984-90). In 1963 he became a member of the Sandinista National Liberation Front and organized urban resistance to the corrupt dictatorship of the Somoza family. Jailed and later exiled, he returned secretly to Nicaragua and helped unite opposition to Somoza. After the Sandinistas prevailed in 1979, he coordinated the rul¬ ing junta; in 1984 he was elected Nicaragua’s president. U.S. efforts to destabilize his government led to economic hardship and a protracted war, and Ortega lost his bid for reelection in 1990, 1996, and again in 2001. See also Violeta Chamorro; contras.

Ortega y Gasset Vor-'ta-ga-e-ga-'setX, Jose (b. May 9, 1883, Madrid, Spain—d. Oct. 18, 1955, Madrid) Spanish philosopher. He taught at the University of Madrid from 1911 and lived abroad from 1931 to 1946. Though influenced by Neo- Kantianism, he diverged from it in works such as Adam in Paradise (1910), Quixote’s Meditations (1914), and Modern Theme (1923). He saw individual life as the fundamental reality; for abso¬ lute reason he substituted reason as a function of life; for absolute truth he substituted the perspective of each individual. Sharing his generation’s preoccupation with Spain’s problems, he founded the periodicals Espaha (1915), El sol (1917), and Revista de Occidente (1923). Of his other works, the best known are Invertebrate Spain (1922) and The Revolt of the Masses (1929), which foreshadowed the Spanish Civil War. He greatly influenced Spain’s 20th-century cultural and literary renaissance.

orthoclase V6r-th3-,klas\ Common alkali feldspar mineral, potassium aluminosilicate (KAlSi 3 O g ), that usually occurs as variously coloured grains in granite. Orthoclase is used in the manufacture of glass and ceramics; occasionally, transparent crystals are cut as gems. It is prima¬ rily important as a rock-forming mineral, however, and is abundant in IGNEOUS ROCKS, PEGMATITES, and GNEisses. The feldspar minerals con¬ sist of sodium, potassium, and cal¬ cium aluminosilicates, and any feldspar may be chemically classed by the percentage of each of these three pure compounds, called end- members. Orthoclase is the potassium-bearing end-member of the sys¬ tem. Microcune is a lower temperature structural form of the same chemical composition as orthoclase.

Orthodox Catholic Church See Eastern Orthodoxy

Orthodox Judaism Religion of Jews who adhere strictly to tradi¬ tional beliefs and practices; the official form of Judaism in Israel. Ortho¬ dox Jews hold that both the written law (Torah) and the oral law (codified in the Mishna and interpreted in the Talmud) are immutably fixed and remain the sole norm of religious observance. Orthodox Judaism has held fast to such practices as daily worship, dietary laws, intensive study of the Torah, and separation of men and women in the synagogue. It also enjoins strict observance of the Sabbath and does not permit instrumental music during communal services. A leading center of Orthodoxy in the U.S. is New York’s Yeshiva Univ.

orthogonal polynomials A system of polynomials that are mutually orthogonal (orthogonality is the higher-dimensional analog of perpen¬ dicularity), useful in solving differential equations arising in physics and engineering. The study of such systems began with Adrien-Marie Le¬ gendre (1752-1833), who employed a system now known as Legendre polynomials in the solution of problems in celestial mechanics. Other famous examples are the sets of Hermite and Chebyshev polynomials.

orthogonality Xor-.tha-go-'na-lo-teV In mathematics, a property syn¬ onymous with perpendicularity when applied to vectors but applicable

Orr (number 4), 1968

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Orthoclase from Serra de Peneda, Portugal

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1420 I orthopedics ► Osceola

more generally to functions. Two elements of an inner product space are orthogonal when their inner product—for vectors, the dot product (see vector operations); for functions, the definite integral of their product—is zero. A set of orthogonal vectors or functions can serve as the basis of an inner product space, meaning that any element of the space can be formed from a linear combination (see linear transformation) of the elements of such a set.

orthopedics \,6r-th3-'pe-diks\ or orthopedic surgery Medical specialty concerned with the skeleton and its associated structures. Ortho¬ pedists treat fractures, strained muscles, torn ligaments and tendons, and other injuries and deal with acquired and congenital skeletal deformities and the effects of degenerative diseases such as osteoarthritis. Originally dependent on heavy braces and splints, orthopedics now uses bone grafts, hip and other joint replacements, prostheses (see prosthesis), special foot¬ wear, and braces to enhance mobility. Orthopedics uses the techniques of PHYSICAL MEDICINE AND REHABILITATION and OCCUPATIONAL THERAPY in addition tO those of traditional medicine and surgery.

Orton, Joe orig. John Kingsley Orton (b. Jan. 1, 1933, Leicester, Leicestershire, Eng.—d. Aug. 9, 1967, London) British dramatist. Origi¬ nally an unsuccessful actor, he turned to writing, finding success in 1964 when his radio play The Ruffian on the Stair was broadcast by the BBC. His three full-length plays. Entertaining Mr. Sloane (1964), Loot (1965), and What the Butler Saw (produced posthumously, 1969), were black comedies that scandalized audiences with their examination of moral cor¬ ruption, violence, and sexual rapacity. Orton’s career was cut short when he was murdered by K.L. Halliwell, his lifelong companion, who after¬ ward committed suicide.

and various dark markings on the body and legs. Both sexes have long, sharp-tipped, straight or curved horns.

Osage \o-'saj\ North American Plains Indian people living mostly in Oklahoma, U.S. Their language is Siouan. The name Osage is a French- derived version of their name for themselves, Wazhazhe. They lived vari¬ ously in the Piedmont and Ozark plateaus and the western Missouri and southeastern Kansas prairies. Their culture was marked by the combina¬ tion of village agriculture and buffalo hunting. Their villages consisted of longhouses; tepees were used during the hunting season. Their religious ceremonies divided clans into symbolic sky and earth groups. In the late 19th century the Osage were removed to a reservation in Oklahoma. The discovery of oil there made them a uniquely prosperous tribe. They num¬ ber more than 18,000.

Osage \o-'saj, 'o-,saj\ River River, western Missouri, U.S. Formed by the junction of the Marais des Cygnes and Little Osage rivers, it is about 500 mi (800 km) long and is one of the principal tributaries of the Mis¬ souri River. It flows east and northeast through Lake of the Ozarks and enters the Missouri just east of Jefferson City, Mo.

Osaka \o-'sa-ka,\ Japanese Vo-sa-ka\ ancient Naniwa City (pop., 2000 prelim.: 2,598,589) and seaport, west-central Honshu, Japan, on the northeastern shore of Osaka Bay. A long-established city and port, Naniwa was made a castle town by Toyotomi Hideyoshi in the 16th century. It was the leading commercial city of Japan during the Tokugawa period and the leading industrial city from the late 19th century. It was badly damaged by U.S. bombing during World War II. Once noted for its large textile indus¬ try, it is now a leading financial centre with heavy industries including machinery, iron and steel, and chemicals. With Kobe and Kyoto, it is part of Japan’s second largest urban and industrial agglomeration. It is also a cultural and educational centre, with several universities and theatres.

Orumiyyeh, Daryacheh-ye See Lake Urmia

Orwell, George orig. Eric Arthur Blair (b. 1903, Motihari, Ben¬ gal, India—d. Jan. 21, 1950, Lon¬ don, Eng.) British novelist, essayist, and critic. Instead of accepting a scholarship to a university, Orwell went to Burma to serve in the Indian Imperial Police (1922-27), an expe¬ rience that changed him into a liter¬ ary and political rebel. On returning to Europe, he lived in self-imposed poverty, gaining material for Down and Out in Paris and London (1933), and became a socialist. He went to Spain to report on the Spanish Civil War and stayed to join the Republi¬ can militia. His war experiences, which gave him a lifelong dread of communism (he would later provide George Orwell.

British intelligence services with BBC copyright lists of his fellow British commu¬

nists), are recounted in Homage to Catalonia (1938). His novels typi¬ cally portray a sensitive, conscien¬ tious, emotionally isolated individual at odds with an oppressive or dishonest social environment. His most famous works are the anti- Soviet satirical fable Animal Farm (1945) and Nineteen Eighty-four (1949), a dystopic vision of totali¬ tarianism whose influence was widely felt in the postwar decades. His literary essays are also admired.

oryx Any of four species (genus Oryx) of large stocky antelopes living in herds on African and Arabian deserts and plains. Oryxes are 40^-7 in. (102-120 cm) high. They have a mane and a tufted tail. The coat is grayish brown, whitish, or white, depending on the species, with dark patches on the face and forehead, a dark streak on either side of the eye,

Arabian oryx (Oryx leucoryx)

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Osborne, John (James) (b. Dec. 12, 1929, London, Eng.—d. Dec. 24, 1994, Shropshire) British play¬ wright and film producer. Initially an actor, he cowrote his first play. The Devil Inside Him (1950), with Stella Linden. His Look Back in Anger (1956; film, 1959) ushered in a spate of vigorously realistic plays about contemporary British working-class life, making Osborne the first of the postwar Angry Young Men. His next play, The Entertainer (1957; film,

1960), told the story of a failing music-hall comedian; it was com¬ missioned by the actor Laurence Oliv¬ ier, who starred in the stage and film versions. Osborne wrote the screen¬ play for the film Tom Jones (1963,

Academy Award), and his other plays include Luther (1961) and Inadmissible Evidence (1964).

Oscan \'as-kon\ language Italic anguage formerly spoken in south¬ ern and central Italy, related closely to Umbrian and more distantly to Latin. It was probably the native tongue of the Samnite people of Ita¬ ly’s central mountainous region. Oscan was gradually displaced by Latin and apparently became extinct by the end of the 1st century ad. Modem knowledge of it comes from some 250 inscriptions written in a colonial Latin alphabet, the Greek alphabet, and an alphabet derived from that used for Etruscan.

Osceola \,a-se-'6-l3\ (b. c. 1804, Georgia, U.S.—d. Jan. 30, 1838, Charleston, S.C.) Seminole Indian leader during the Second Seminole War. The war began in 1835 when the U.S. government attempted to

John Osborne

UPI/BETTMANN NEWSPHOTOS

Osceola, detail of a lithograph by George Catlin, 1838

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oscillator ► Ostade I 1421

force the Seminole off their traditional lands in Florida and into the Indian territory west of the Mississippi River. Osceola and his followers employed guerrilla tactics and forced a truce. During negotiations he was arrested and removed to a military fort at Charleston, S.C., where he died.

oscillator Mechanical or electronic device that produces a back-and- forth periodic motion. A pendulum is a simple mechanical oscillator that swings with a constant amplitude, requiring the addition of energy at each swing only to compensate for the energy lost because of air resistance or friction. In electronic oscillators, electrons oscillate with a constant period and also require the addition of energy to replace energy loss. Electronic oscillators are used to generate alternating current and high-frequency currents for carrier waves in radio broadcasting. They are incorporated in a wide variety of electronic equipment.

oscilloscope \3-'si-l3-,skop\ or cathode-ray oscilloscope Elec¬ tronic display device used to produce patterns on a screen that are the graphical representations of electrical signals. Time is normally on the horizontal axis, and a function of the voltage generated by the input sig¬ nal to the oscilloscope on the vertical axis; four or more plots can be simultaneously shown. Because almost any physical phenomenon can be converted into a corresponding electric voltage, oscilloscopes find com¬ mercial, engineering, and scientific applications in acoustic research, television-production engineering, and electronics design.

Oshogbo \5-'shog-bo\ City (pop., 1996 est.: 476,800), Nigeria. Located northeast of Ibadan, it lies along the Oshun River. Originally settled by the Ilesha from Ibokun, it remained a small town until the early 19th cen¬ tury when an influx of Yoruba fleeing from Fulani conquerors arrived. In 1840 it was the scene of a battle won by Ibadan that proved to be the turning point in the Fulani-Yoruba wars. It was made part of Oyo state in 1976 and the capital of the newly created state of Osun in 1991. It is a trade centre for cocoa and palm oil; weaving and dyeing cotton cloth and growing tobacco are other local occupations.

Osiris \o-'sI-r3s\ Ancient Egyptian god of the underworld. Osiris was slain by the god Seth, who tore apart the corpse and flung the pieces all over Egypt. The goddess Isis, consort of Osiris, and her sister Nephthys found the pieces and gave new life to Osiris, who became the ruler of the underworld. Isis and Osiris then conceived Horus. In the Egyptian con¬ cept of divine kingship, the king at death became Osiris and the new king was identified with Horus. Osiris also represented the power that brought life out of the earth. Festivals reenacting his fate were celebrated annu¬ ally in towns throughout Egypt.

Osier Vos-lorV, Sir William (b. July 12, 1849, Bond Head, Canada West, Can.—d. Dec. 29, 1919,

Oxford, Oxfordshire, Eng.) Cana¬ dian physician and professor. He became the first to identify blood platelets (1873) and later taught at the medical school at McGill University (1875-84) and then at Johns Hop¬ kins University’s medical school (1889-1905). There he helped trans¬ form clinical teaching; students stud¬ ied patients in the wards and took their problems to the lab, and experts pooled their knowledge to benefit both patient and student in public teaching sessions. Osier’s Principles and Practice of Medicine (1892) became the most popular medical textbook of its day. He was involved in the formation of two physicians’ associations and the Quarterly Jour¬ nal of Medicine. Osier nodes on the hand are seen in some cardiac infec¬ tions, and two blood disorders also bear his name.

Oslo \'az-lo,\ Norwegian Vus-lu\ formerly (1624-1925) Christiania City and municipality (pop., 2002 est.: municipality, 512,589), capital of Norway. It lies at the northern end of Oslo Fjord and constitutes a separate county. It was founded by King Harald III Sigurdsson c. 1050. Haakon V built the Akershus fortress c. 1300. After it was destroyed by fire in 1624, King Christian II of Denmark-

Norway built a new town farther west and called it Christiania. It grew in the 19th century, partly by absorbing neighbouring towns, and replaced Bergen as Norway’s largest and most influential city. It was renamed Oslo in 1925 and developed rapidly after World War II. It is the country’s prin¬ cipal commercial, industrial, and transportation centre, and its harbour is the largest and busiest in Norway.

osmosis \az-'mo-s3s\ Spontaneous passage or diffusion of water or other solvent through a semipermeable membrane. If a solution is separated from a pure solvent by a membrane that is permeable to the solvent but not to the solute, the solution will tend to become more dilute by absorb¬ ing solvent through the membrane. The pressure caused by the migration of solvent through the membrane is called osmotic pressure.

osprey Vas-pre, 'as-pra\ or fish hawk Species (Pandion haliaetus ) of long-winged hawk found along seacoasts and large interior waterways. Ospreys are about 26 in. (65 cm) long and brown above and white below, with some white on the head. An osprey flies over the water, hovers above its prey, and then plunges feet first, seizing the fish in its long, curved talons. Ospreys breed on all continents except South America, where they live only in winter. They usually nest, singly or in colonies, high in trees or on cliffs. Bioaccumulation of pesticides caused populations to dwindle in the 20th century, but they are now recovering.

Osroene or Osrhoene \,az-r3-'we-ne\ Ancient kingdom, northwest¬ ern Mesopotamia. Located between the Tigris and Euphrates rivers, it was situated across the modem frontier of Turkey and Syria, with its capital at Edessa (modem Sanliurfa, Tur.). Founded in c. 136 bc, it commanded strategic trade and military routes (1st century BC-2nd century ad). At dif¬ ferent times it was allied with either Parthia or Rome. The kingdom was abolished by the Roman emperor Caracalla in ad 216. In the 4th-7th cen¬ turies ad it was dominated by the wars between the Byzantine Empire and the Persian Sasanian dynasty. Under various Arab dynasties, it became a centre of reaction against Hellenism and the headquarters of Chaldean Syriac literature and learning. It fell to the Muslims in 638.

OSS See Office of Strategic Services

Osservatore Romano yo-.ser-va-'to-ra-ro-'ma-noV 1/ Italian "The Roman Observer" Daily newspaper published in Vatican City, one of the most influential papers in Italy and the de facto voice of the Holy See. Founded in 1861, it was subsidized by the Vatican from its start and was bought outright in 1890 by Pope Leo XIII. It regularly details the pope’s activities and prints the text of papal speeches as the Vatican newspaper of record; it also reports and comments on political developments, stress¬ ing editorials and commentary over news and noting the religious and moral implications of events, institutions, and trends.

Ossian Vas-e-on, 'ash-on \ Gaelic Oisin Vosh-yin\ Irish warrior-poet of the Fenian cycle of hero tales. The name Ossian became known throughout Europe in 1762-63 when the Scottish poet James Macpherson (1736-96) published the epics Fingal and Temora, which he represented as transla¬ tions of works by the 3rd-century Gaelic poet Ossian. The poems were widely acclaimed and influential in the Romantic movement, but their authorship was later doubted, notably by Samuel Johnson (1775), and they were eventually determined to have been written largely by Macpherson.

Ossianic ballads \,a-se-'a-nik, .a-she-'a-nikX Irish Gaelic and Scottish lyric and narrative poems dealing with the legendary Finn MacCumhaill and his war band. They are named for Oisfn (Ossian), the chief bard of the Fenian cycle. Part of a common Scots-Irish Gaelic tradition, the bal¬ lads consist of more than 80,000 lines dating from the 11th to the 18th century. Unlike earlier Fenian literature, which reflected mutual respect between pagan and Christian tradition, they are stubbornly pagan and anticlerical, full of lament for past glories and contempt for the Christian present. Most of the poetry claimed for Oisfn was in fact written by Scot¬ tish poet James Macpherson (1736-1796).

Ossianic cycle See Fenian cycle

Ossory \'a-so-re\ Ancient kingdom, Ireland. It became a semi¬ independent state within the kingdom of Leinster (c. 1st century ad). In the 9th century its king, Cerball, allied himself with the Norse invaders. His Irish descendants became known as the Fitzpatricks. The modem dio¬ cese of Ossory, with its see at Kilkenny, approximates the size of the ancient state.

Ostade \os-'ta-d3\, Adriaen van (b. Dec. 10, 1610, Haarlem, Neth.—buried May 2, 1685, Haarlem) Dutch painter and printmaker.

William Osier, at the bedside of a patient, while professor of medicine at Johns Hopkins, 1888-1904.

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1422 I Ostend ► O'Sullivan

Known for his Baroque genre paintings of peasant life, he also did reli¬ gious subjects, portraits, and landscapes. The most important influence on his style was the work of Adriaen Brouwer. Like Brouwer, he delighted in scenes such as tavern brawls, usually in dimly lit interiors, as in Carous¬ ing Peasants in an Interior (c. 1638). He employed a broad, vigorous technique in a subdued range of colours. After he adopted a brighter pal¬ ette in the 1640s, his subjects became less ribald, and from the 1650s he painted many of them in outdoor settings.

Ostend \a-‘stend\ Manifesto (1854) Secret document written by U.S. diplomats at Ostend, Belg., describing a plan to acquire Cuba from Spain. On orders from U.S. secretary of state William Marcy, three U.S. diplomats—minister to Britain James Buchanan, minister to France John Y. Mason, and minister to Spain Pierre Soule—devised a plan to purchase or, if necessary, seize Cuba for the U.S. Publication of the aggressively worded document, and Soule’s advocacy of slavery, caused Marcy to denounce it.

osteoarthritis V.as-te-o-ar-'thri-tosX or osteoarthrosis or degen¬ erative joint disease Most common joint disorder, afflicting over 80% of those who reach age 70. It does not involve excessive inflamma¬ tion and may have no symptoms, especially at first. Cartilage softens and wears away, and bone grows in its place, distorting the joint’s surface and causing pain, stiffness, and limited movement, usually in weight-bearing joints (vertebrae, knees, hips). Treatment may include analgesics, rest, weight loss, corticosteroids, and/or physical medicine and rehabilitation or an exercise program. Hip or knee replacement or surgical removal of unhealthy tissue may be needed.

osteogenesis imperfecta V.as-te-o-'je-no-sos-.im-por-'fek-toN Group of connective-tissue diseases in which the bones are very fragile. Several forms probably reflect different degrees of expression of the same disor¬ der. Persons with osteogenesis imperfecta type I are normal at birth, but fractures occur easily; in van der Hoeve syndrome the sclerae are bluish, bone deformities in the skull cause deafness, double-jointedness occurs, and skin is abnormally thin. Babies with osteogenesis imperfecta type II, if not stillborn, are born with fractures, and fractures continue to occur, causing severe crippling; survival to adulthood is rare.

osteopathy \,as-te-'a-p3-the\ Health-care profession founded by the U.S. physician Andrew Taylor Still (1828-1917) as a reform movement against the rather primitive 19th-century drugs and surgical techniques. It emphasizes the relationship between musculoskeletal structure and organ function. Osteopathic physicians learn to recognize and correct structural problems through manipulative and other therapies. Osteopathic hospitals provide general or specialized health care, including maternity and emergency care.

osteoporosis \,as-te-6-p3-'ro-s9s\ Generalized loss of bone density, causing skeletal weakness. Around age 40, the rate of bone resorption in humans starts to exceed the rate of bone formation. Women experience accelerated bone loss after menopause, when the estrogen level decreases. When the amount of bone falls below a certain threshold, fractures occur with little or no trauma. Prevention begins with adequate calcium intake in youth, when bone mass is built, and then throughout life. Weight¬ bearing exercise and vitamin D are important at all ages. Medications can inhibit bone resorption or prevent bone loss in patients who are at risk for developing osteoporosis.

Ostia \'a-ste-o\ Ancient Roman town. Originally at the mouth of the Tiber River, it would now be about 4 mi (6 km) upstream. The modern seaside resort of Ostia, Italy, is near the ancient city. It was probably founded in the 4th century bc and developed as a naval station, major port, and cen¬ tre of the grain trade. It reached the height of its prosperity in the 2nd century ad, when it had a population of about 50,000. It suffered from the decline of the Roman economy in the 3rd century and from barbarian raids in the 5th century. Its Roman ruins were quarried for building materials in the Middle Ages and for sculptors’ marble during the Renaissance. Excavations began in the 19th century, and about two-thirds of the Roman town can now be seen.

ostomy Vas-t3-me\ Surgical opening in the body, or the operation cre¬ ating it, usually to allow discharge of wastes through the abdominal wall. It may be temporary, to relieve strain on damaged organs, or permanent, to replace normal channels congenitally missing or surgically removed (usually to treat cancer). A loop of bowel (the colon in colostomy and the ileum in ileostomy) is cut and the end brought through to the abdominal

surface. Waste usually exits into a self-adhering bag worn over the open¬ ing, or an internal pouch may be made from body tissue.

Ostpolitik Vost-po-li-.tekX (German: “Eastern Policy”) West German foreign policy begun in the late 1960s. Initiated by Willy Brandt as for¬ eign minister and then chancellor, the policy was one of detente with Soviet-bloc countries, recognizing the East German government and expanding commercial relations with other Soviet-bloc countries. Trea¬ ties were concluded in 1970 with the Soviet Union, renouncing the use of force in their relations, and with Poland, recognizing Germany’s 1945 losses east of the Oder-Neisse Line. The policy was continued by Chancel¬ lor Helmut Schmidt.

Ostrasia See Austrasia

Ostrava Vo-stro-vsX City (pop., 2001 prelim.: 319,293), northeastern Czech Republic, at the confluence of the Opava and Oder rivers near the Moravian Gap. It was founded c. 1267 as a fortified town by Bruno, bishop of Olomouc, to protect the entry to Moravia from the north. Its castle was demolished in 1495. Historic buildings include a 13th-century church.

ostrich Two-toed, long-necked ratite ( Struthio camelus, family Struthionidae) found in Africa, the largest living bird. An adult male ostrich may be nearly 9 ft (2.75 m) tall and weigh more than 330 lb (150 kg). Males are black, with white wing and tail plumes; females are brown. Ostriches live in flocks of 5-50, usually among grazing animals, and eat plants and an occasional small animal. Roaring, hissing males fight for three to five hens, which lay 15-60 eggs in a communal nest scraped in the ground. The male sits at night; the females take turns by day. One- month-old chicks can run with adults, at 40 mph (65 km/hr). To escape detection, an ostrich may lie on the ground with its neck outstretched, a habit that may have given rise to the notion that ostriches bury their heads in the sand.

Ostrogoth Vas-tro-.gathV Member of a division of the Goths (Ostrogoth means “Eastern Goth”) who built an empire north of the Black Sea in the 3rd century and established a kingdom in Italy in the late 5th century. At its zenith in the 4th century, the Ostrogoth empire stretched from the Don to the Dniester (in present-day Ukraine) and from the Black Sea to southern Belarus. The Ostrogoths were conquered by the Huns c. 370 and remained part of the Huns’ empire until the mid 5th century. When the Hun empire collapsed (455), the Ostrogoths emerged as an independent people once again. Their greatest ruler, Theodoric, led the Ostrogothic invasion of Italy and declared himself king (493). Theodoric maintained good relations with the native population, especially the senatorial class, throughout most of his reign and promoted a cultural revival. The turmoil in Italy following his death provided the Byzantine emperor Justinian I with the opportunity to invade the peninsula. The ensuing war lasted almost 20 years (c. 535-54) and ended the national existence of the Ostrogoths.

Ostrovsky V.o-'strof-skeV, Aleksandr (Nikolayevich) (b. April 12, 1823, Moscow, Russia—d. June 14, 1886, Shchelykovo) Russian playwright. His second play, The Bankrupt (1850), exposed bogus bank¬ ruptcy cases and led to his dismissal from the civil service. Most of his plays treat characters from the Russian merchant class; they include the comedies Poverty Is No Disgrace (1853), The Thunderstorm (1859), and The Snow Maiden (1873), adapted as an opera by Nikolay Rimsky- Korsakov. With his 47 plays Ostrovsky created a Russian national reper¬ toire, and he is considered the greatest representative of the Russian realistic period.

Ostwald \'6st-,valt\, (Friedrich) Wilhelm (b. Sept. 2, 1853, Riga, Latvia—d. April 4, 1932, near Leipzig, Ger.) Russian-German physical chemist. He moved to Germany in 1887. He wrote the influential Text¬ book of General Chemistry, 2 vol. (1885-87). With Jacobus H. van't Hoff in 1887 he founded the Zeitschrift fur physikalische Chemie, which became for many years the most important journal in the field. His work at the University of Leipzig (1887-1906) established it as a great school of physical chemistry. In 1888 he discovered Ostwald’s law of dilution of an electrolyte. He gave the first modem definition of a catalyst in 1894 and was awarded the Nobel Prize in 1909 for his work on catalysis. His process for the conversion of ammonia to nitric acid proved of great industrial importance. He is regarded as one of the founders of the field of physical chemistry.

O'Sullivan, Timothy H. (b. c. 1840, New York, N.Y., U.S.—d. Jan. 14, 1882, Staten Island, N.Y.) U.S. photographer. He learned photogra-

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Oswald ► otter I 1423

phy in Mathew B. Brady’s studio in New York City, and during the Ameri¬ can Civil War he photographed on many fronts as one of Brady’s team. Perhaps his best-known picture is Harvest of Death (1863), showing Con¬ federate dead at Gettysburg. O’Sullivan left Brady’s employ over the issue of receiving proper credit for his work. After the war O’Sullivan often portrayed vast landscapes. He took part in surveys in Panama as well as in the western and southwestern U.S. and was appointed chief photogra¬ pher for the Treasury Department in 1880.

Oswald, Lee Harvey (b. Oct. 18, 1939, New Orleans, La., U.S.—d. Nov. 24, 1963, Dallas, Texas) Accused assassin of Pres. John F. Kennedy. While serving in the U.S. Marines (1956-59) he began to express pro- Soviet and politically radical views. Shortly after his discharge he moved to the Soviet Union, where he unsuccessfully tried to become a Soviet citizen. He returned to the U.S. in 1962 with his Russian wife and daugh¬ ter but retained his radical political beliefs. In April 1963 he allegedly shot at but missed Edwin Walker, an ultrarightist retired general. In Octo¬ ber he took a job at the Texas School Book Depository in Dallas. On Nov. 22, 1963, from a window on its sixth floor, he allegedly fired three shots that killed Kennedy and wounded Gov. John B. Connally while the two men were riding in the president’s motorcade. Oswald killed a patrolman who had detained him, but he was soon captured and arraigned. On November 24, while being transferred to an interrogation office, he was fatally shot by Jack Ruby, a nightclub owner.

other minds, problem of In epistemology, the problem of explain¬ ing how it is possible for one person to know anything about the quality of another person’s inner experience, or even that other people have inner experiences at all. According to a standard example, because each per¬ son’s pain sensation is private, one cannot really know that what another person describes as pain is really qualitatively the same as what one describes as pain oneself. Though the physical manifestations the other person exhibits can be perceived, it seems that only the other person can know the contents of his mind. The traditional justification for belief in other minds, the argument from analogy, was given its classic formula¬ tion by John Stuart Mill: because my body and outward behaviour are observably similar to the bodies and behaviour of others, I am justified by analogy in believing that others have feelings like my own and are not simply automatons. In the mid-20th century the argument from analogy was severely criticized by followers of the later Ludwig Wittgenstein. An approach to the problem of other minds from the perspective of existen¬ tialism is contained in Being and Nothingness (1943), by Jean-Paul Sartre.

Otis, Harrison Gray (b. Oct. 8, 1765, Boston, Mass.—d. Oct. 28, 1848, Boston, Mass., U.S.) U.S. politician. A nephew of James Otis, he practiced law and served in the Massachusetts legislature (1796-97, 1802-05), the U.S. House of Representatives (1797-1801), the state sen¬ ate (1805—13, 1814-17), and the U.S. Senate (1817-22). He was later mayor of Boston (1829-32). A Federalist, he opposed the War of 1812 and was a leader of the Hartford Convention.

Otis, James (b. Feb. 5,1725, West Barnstable, Mass.—d. May 23,1783, Andover, Mass., U.S.) American Revolutionary statesman. He argued before the colonial court against the British-imposed writs of assistance (1761), reportedly stating “Taxation without representation is tyranny.’’ He served in the provincial legislature (1761-69) and was a leading opponent, along with Samuel Adams, of the Stamp Act. He wrote political pamphlets upholding the colonists’ cause, including The Rights of the British Colonies Asserted and Proved (1764). Struck on the head in a scuffle with a British official in 1769, he later became mentally unbalanced.

otitis \o-'tI-t9s\ Inflammation of the ear. Otitis externa is dermatitis, usu¬ ally bacterial, of the auditory canal and sometimes the external ear. It can cause a foul discharge, pain, fever, and sporadic deafness. Otitis media is due to allergy or viral or bacterial infection of the middle ear. The bac¬ terial form may be acute (causing earache, fever, and pus and requiring antibiotics) or chronic. It can invade the bone (mastoiditis), requiring sur¬ gery. Otitis in the inner ear (labyrinthitis) often arises from respiratory infection, syphilis, or otitis media. Symptoms include vertigo, vomiting, and hearing loss. Recovery is usually quick unless there is pus formation, which can destroy the inner-ear structures, causing permanent deafness in that ear.

otolaryngology V.o-to-.lar-on-'ga-lo-jeV or otorhinolaryngology

X.o-to-.rl-no-.lar-on-'ga-lo-jeV Medical specialty dealing with the ear, nose, and throat (see larynx, pharynx). The connection of these structures became known in the late 19th century. Otolaryngologists use an otoscope to

examine the eardrum and a laryngoscope (developed in 1855) to inspect the larynx. They also test hearing and prescribe hearing aids. The oper¬ ating microscope (developed in 1921) and flexible endoscopy now permit them to operate on delicate internal structures.

Otomanguean \,o-t3-'maq-ga-3n\ languages Diverse family of more than 20 American Indian languages and language clusters concen¬ trated in central and southern Mexico, with more than a million speak¬ ers. Several of the language clusters, such as Otomf (dispersed through eastern central Mexico), Chinantecan, Mixtecan, and Zapotecan (all spo¬ ken in the state of Oaxaca), are highly differentiated and may be consid¬ ered language families in themselves. Otomanguean languages differ in many ways from other American Indian languages, for example, in the extensive use of tone.

Otomi V.o-to-'meN Mesoamerican Indian population living in the central plateau region of Mexico. Traditionally, they practice shifting cultivation and raise livestock. Their crafts include spinning, weaving, pottery, and basketry, and their dress varies from traditional to modem. Compadrazgo, Active kinship based on the relationship of godparent to godchild, is cen¬ tral to their society. Ritual obligations also bind a child’s parents and god¬ parents in a close relationship. They profess Roman Catholicism but identify the major saints with pre-Christian deities.

O'Toole, Peter (Seamus) (b. Aug. 2, 1932, Connemara, County Gal¬ way, Ire.) British actor. He studied drama at the Royal Academy of Dra¬ matic Art. He made his London debut in 1956 and played Hamlet in the National Theatre’s inaugural production in 1963. His film debut came in Kidnapped ( 1960), and he won international acclaim for Lawrence of Ara¬ bia (1962), for which he won a British Academy Award. Noted for his wit and intensity, he often played uncertain heroes or eccentrics, starring in films such as Becket (1964), The Lion in Winter (1968), The Ruling Class (1972), The Stunt Man (1980), My Favorite Year (1982), The Last Emperor (1987), and Phantoms (1998). His acting range extends from classical drama to contemporary farce. He received an Emmy Award for his perfor¬ mance as Bishop Cauchon in the television miniseries Joan of Arc (1999).

otorhinolaryngology See otolaryngology

ottava rima Xo-'ta-vo-'re-moV Italian stanza form composed of eight 11-syllable lines, rhyming abababcc. It originated in the late 13th and early 14th centuries and was established by Giovanni Boccaccio as the standard form for Italian epic and narrative verse. When the form appeared in English, the lines were shortened to 10 syllables. In the 17th—18th cen¬ tury, English ottava rima was written in iambic pentameter and used for heroic poetry. Notably effective in Lord Byron’s Beppo (1818) and Don Juan (1819-24), it was also used by Edmund Spenser, John Milton, John Keats, Percy B. Shelley, Robert Browning, and William Butler Yeats.

Ottawa Va-to-woV City (pop., 2001: 774,072), capital of Canada. It is located in southeastern Ontario, on the Ottawa, Gatineau, and Rideau rivers. The area was inhabited by American Indians when it was visited by Samuel de Champlain in 1613, and the nearby rivers served traders and explorers over the next two centuries. Its settlement developed after the construction of the Rideau Canal in 1826. Originally named Bytown, it was incorporated as the city of Ottawa in 1855. To resolve political dis¬ putes between Toronto and Quebec City and between Montreal and Kings¬ ton, it was selected as Canada’s capital by Queen Victoria in 1857. In 2001 the city’s population grew significantly after it was amalgamated with several local municipalities. The federal government is the major employer; many commercial and financial associations are also located there. It is the site of several educational and cultural institutions, includ¬ ing the National Arts Centre and the National Gallery of Canada.

Ottawa River River, eastern central Canada, the chief tributary of the St. Lawrence River. It rises in the Laurentian plateau of western Quebec and flows west to form the Quebec-Ontario border before joining the St. Lawrence west of Montreal. It is 790 mi (1,271 km) long and forms innu¬ merable lakes. Explored by Samuel de Champlain in 1613, it became a major route for explorers, fur traders, and missionaries to the Great Lakes. In the 19th century the Rideau Canal was completed, linking Ottawa to Lake Ontario, and lumbering became important. It is now a source of hydro¬ electric power.

otter Any of 13 species of semiaquatic, web-footed carnivores in the weasel family (Mustelidae), found throughout Africa, North and South America, Europe, and Asia. Otters have the same general proportions as weasels. Size varies among species, but total length is typically 3-7 ft

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1424 I Otto I ► Ouagadougou

(1-2 m), and weight is 6.5-60 lb (3-26 kg); the large sea otter is an exception. Otter fur—e.g., that of North American river otters—is highly valued. Most species live near rivers, some live near lakes or streams, and the sea otter is com¬ pletely marine. Otters eat small aquatic animals. They are inquisitive and playful; a favourite sport is slid¬ ing down mud or snow banks.

Otto I known as Otto the Great

(b. Nov. 23, 912—d. May 7, 973,

Memleben, Thuringia) Duke of Sax¬ ony (936-61), German king (936- 73), and emperor (962-73). He extended the frontiers of the German kingdom, winning territory from the Slavs in the east, forcing the Bohe¬ mians to pay tribute (950), and gaining influence in Denmark and Bur¬ gundy. In 951 Otto became king of the Lombards and married the queen of Italy. He quelled a rebellion by his son in 955 and defeated the Mag¬ yars in the Battle of Lechfeld. Crowned emperor by Pope John XII in 962, he deposed John in 963 and replaced him with Leo VIII. He returned to Italy (966-72) to subdue Rome, and he betrothed his son, Otto II, to a Byzantine princess (972). He also extended his authority over the church and promoted missionary activity in lands he had conquered. By his death, Otto had created the most powerful state in western Europe and laid the foundation for the later Holy Roman Empire.

Otto III (b. July 980—d. Jan. 23, 1002, near Viterbo, Italy) German king (983-1002) and emperor (996-1002). He was elected German king at age 3, and his mother and grandmother served as regents until he came of age in 994. He went to Rome to put down a rebellion (996) and installed his cousin as Gregory V, the first German pope. After returning in 997 to quell another revolt, he made Rome the centre of his empire. He saw himself as leader of world Christianity and hoped to revive the glory of ancient Rome in a universal Christian state. When Rome rebelled against him (1001), he requested help from Bavaria but died before it arrived.

Otto IV or Otto of Brunswick (b. 1175/1182—d. May 19, 1218, Harzburg Castle, Lower Saxony) German king and Holy Roman emperor. He was elected German king (1198) by the Guelph faction (see Guelphs and Ghibellines) but was opposed by the Hohenstaufens, who elected Philip of Swabia. The two factions were at war for several years, but after Phil¬ ip’s murder in 1208 a new election gave the throne to Otto. He was crowned emperor (1209) by Pope Innocent III after agreeing not to claim Sicily. When he violated this pact and conquered southern Italy (1210), the German princes invited Frederick II to replace him. With his uncle, John of England, Otto invaded France, Frederick’s ally; defeated at the Battle of Bouvines, he was deposed in 1215.

religion were influenced by his journeys to Africa and Asia to study non- Christian faiths and by the writings of Immanuel Kant and Friedrich Schleier- macher. In The Idea of the Holy (1917), Otto coined the term numinous to designate the nonrational element of religious experience—the awe, fascination, and blissful exultation inspired by the perception of the divine. He believed that religion provided an understanding of the world that was distinct from and beyond that of science. His other books include Mysticism East and West (1926), India's Religion of Grace and Chris¬ tianity (1930), and The Kingdom of God and Son of Man (1938).

Ottoman Empire Former empire centred in Anatolia. It was named for Osman I (1259-1326), a Turkish Muslim prince in Bithynia who con¬ quered neighbouring regions once held by the SeuOq dynasty and founded his own ruling line c. 1300. Ottoman troops first invaded Europe in 1345, sweeping through the Balkans. Though defeated by Timur in 1402, by 1453 the Ottomans, under Mehmed II (the Conquerer), had destroyed the Byzan¬ tine Empire and captured its capital, Constantinople (now Istanbul), which henceforth served as the Ottoman capital. Under Selim I (r. 1512-20) and his son SOleyman I (the Magnificent; 1520-66), the Ottoman Empire reached its greatest peak. Suleyman took control of parts of Persia, most of Arabia, and large sections of Hungary and the Balkans. By the early 16th century the Ottomans had also defeated the MamlOk dynasty in Syria and Egypt; and their navy under Barbarossa soon seized control of much of the Barbary Coast. Beginning with Selim, the Ottoman sultans also held the title of caliph, the spiritual head of Islam. Ottoman power began to decline in the late 16th century. Ottoman forces repeatedly besieged Vienna. After their final effort at taking the Austrian capital failed (1683), that and subsequent losses led them to relinquish Hungary in 1699. Cor¬ ruption and decadence gradually undermined the government. In the late 17th and 18th centuries the Russo-Turkish Wars and wars with Austria and Poland further weakened the empire, which in the 19th century came to be called the “sick man of Europe.” Most of its remaining European ter¬ ritory was lost in the Balkan Wars (1912-13). It sided with Germany in World War 1(1914-18); postwar treaties dissolved the empire, and in 1922 the sultanate was abolished by Mustafa Kemal AtatOrk, who proclaimed the Republic of Turkey the following year. See also Janissary; Turk; Young Turks.

Ottoman \a-'to-ne-3n\ art Painting, sculpture, and other visual arts produced during the reigns of the German Ottoman emperors and their first successors from the Salic house (950-1050). Though it drew on the heritage of Carolingian art, it developed a style of its own, particularly in painting and sculpture. Manuscript illuminators of the period were less concerned with naturalism than with expression through sober, dramatic gesture and a heightened use of colour. Ottoman large-scale wooden cru¬ cifixes and wooden reliquaries covered with gold leaf marked a return to sculpture in the round. Bronze casting, an antique art practiced by the Carolingians, flourished as well. Ottonian architecture was more regulated than Carolingian, with simple interior spaces and a more systematic lay¬ out. Ottonian architects provided impetus for the monumentality of Romanesque architecture.

Otway, Thomas (b. March 3, 1652, Trotton, near Midhurst, Sussex, Eng.—d. April 14, 1685, London) English dramatist and poet. A failed actor, he turned to writing and had immense success with Don Carlos (produced 1676), considered the best of his rhymed heroic plays. His other plays include The Orphan (1680), a blank-verse domestic tragedy; The Souldier’s Fortune (1680), a comedy; and his masterpiece, Venice Preserv’d (1682), one of the greatest theatrical successes of the period. A forerunner of sentimental drama, he is outstanding for his convincing presentations of human emotions in an age of heroic but artificial trag¬ edies. The Poet’s Complaint of His Muse (1680) is a powerful, gloomy autobiographical poem.

Ouachita Vwa-sho-.toX River formerly Washita River River, south¬ western Arkansas and eastern Louisiana, U.S. Rising in the Ouachita Mountains, it flows southeast to join the Red River after a course of 605 mi (973 km). Its lower reaches are known as the Black River. It has been a navigation route since the late 18th century; six locks and dams had been built on it by 1924.

Ouagadougou X.wa-ga-'dii-giA City (pop., 1993 est.: 690,000), capi¬ tal of Burkina Faso, western Africa. It was the capital of the historic Mossi kingdom of Wagadugu, which was founded in the 15th century. The Mossi king still lives in the city, though his powers have been eclipsed by the French colonial and postindependence administrations. A manufacturing

River otter (Lutra canadensis).

KENNETH W. FINK-ROOT RESOURCES

Otto, Nikolaus August (b. June Jan. 26, 1891, Cologne, Ger.) Ger¬ man engineer who developed the four-stroke internal-combustion engine. He built his first gasoline- powered engine in 1861, and in 1876 he built an internal-combustion engine using the four-stroke cycle (four strokes of the piston for each explosion), which offered the first practical alternative to the steam engine as a power source. Though the four-stroke cycle was patented in 1862 by Alphonse Beau de Rochas (1815—93), it is commonly known as the Otto cycle since Otto was the first to build such an engine.

Otto, Rudolf (b. Sept. 25. 1869. Peine, Prussia—d. March 6, 1937, Marburg, Ger.) German theologian, philosopher, and historian of reli¬ gion. He taught at the Universities of Gottingen and Breslau, then settled in Marburg in 1917. His theories on

10, 1832, Holzhausen, Nassau—d.

Rudolf Otto, 1925.

FOTO-JANNASCH, MARBURG

© 2006 Encyclopaedia Britannica, Inc.

Oudh ► over-the-counter market I 1425

centre, it is the country’s largest city and is connected by rail to Abidjan, Cote d’Ivoire. A biennial film festival, the largest in Africa, is held in the city.

Oudh \'aud\ Former province of British India. Now the northeastern portion of Uttar Pradesh state, it received its name from Ayodhya, the capital of the ancient kingdom of Kosala, which was nearly coextensive with modem Oudh. It was taken by Muslim invaders in the 12th century, became part of the Mughal Empire in the 16th century, and was annexed by the British in 1856. In 1877 it was joined with Agra to form the United Provinces of Agra and Oudh. After India’s independence in 1947 it became part of Uttar Pradesh.

Oudry \ii-'dre\, Jean-Baptiste (b. March 17, 1686, Paris, France—d. April 30, 1755, Beauvais) French Rococo painter, tapestry designer, and illustrator. Like his paintings, Oudry’s tapestries were highly regarded for their tonal subtlety and lively study of nature. His services were sought by Peter I the Great of Russia, the queen of Sweden, and Louis XV, who commissioned him to paint portraits of his dogs and appointed him offi¬ cial painter of the royal hunts.

Ouida \'we-do\ orig. Maria Louise Rame or Maria Louise de la Ramee (b. Jan. 1, 1839, Bury St. Edmunds, Suffolk, Eng.—d. Jan. 25, 1908, Viareggio, Italy) English novelist. Among her novels, most of them extravagant, melodramatic romances of fashionable life, are Held in Bondage (1863), Strathmore (1865), Chandos (1866), Under Two Flags (1867), and Moths (1880). She also wrote animal stories, including the popular A Dog of Flanders (1872). She settled in Florence in 1874, where reckless extravagance reduced her to acute poverty in later life.

Ouija board Vwe-jsX Device for obtaining messages from the spirit world, sometimes used by a medium during a seance. The name derives from the French and German words for “yes” (oui/ja). The Ouija board is an oblong piece of wood or cardboard with letters of the alphabet inscribed in a half-moon along the edge. A small heart-shaped board is placed on top of it. Participants each lightly place a finger on the small board, which spirits supposedly move around on the larger board. As it touches the letters it may spell out words or sentences.

ounce Unit of weight in the avoirdupois system, the traditional Euro¬ pean system of weight, which was incorporated into the British Imperial system and the U.S. system of weights and measures (see measurement). The ounce is equal to 1/16 lb (437.5 grains). In the troy and apothecar¬ ies’ systems (two other traditional systems of weight), it is equal to 1/12 troy or apothecaries’ lb (480 grains). The avoirdupois ounce is equal to 28.35 g, the troy ounce to 31.1 g. As a unit of volume, the fluid ounce is equal to 1/16 of a pint (29.57 ml) in the U.S. system, and to 1/20 of a pint (28.41 ml) in the British Imperial system. See also gram. Interna¬ tional System of Units, metric system, pound.

ounce See snow leopard Ouranus See Uranus

Ouse \'uz. River or Great Ouse River, central and eastern England. It rises in Northamptonshire and flows 156 mi (251 km) past Buckingham, Bedford, Huntington, and St. Ives to Earith, then to the North Sea. Locks make the river navigable upstream to Bedford.

Ouse, River River, northeastern England. It is formed in North York¬ shire and flows through York and Selby to join the River Aire. It merges with the River Trent to form the River Humber. The lower Ouse is a major transport route for industrial products and raw materials.

ousel See ouzel

Outer Banks Chain of barrier islands, North Carolina coast, U.S. Extending southward 175 mi (282 km) along the coast, it stretches from the Virginia border to Cape Lookout. Generally covered with sand dunes, the islands range from a few feet to more than 100 ft (160 m) in height. Most are linked by roads and causeways; there are numerous beaches, making the Outer Banks a popular resort area. Once a hideout for pirates and a place of shipwrecks, the islands have several historical sites, includ¬ ing Roanoke Island and Kitty Hawk, site of the Wright brothers’ first pow¬ ered flight.

Outer Mongolia See Mongolia

outwash Deposit of sand and gravel carried by running water from the melting ice of a glacier and laid down in stratified deposits. An outwash

may be as much as 330 ft (100 m) thick at the edge of a glacier, and it may extend for many miles. Outwashes are the largest glacial deposits and provide a considerable source of windblown material.

Ouyang Xiu Vo-'yag-'shyuX or Ou-yang Hsiu (b. 1007, Mianyang, Sichuan province, China—d. 1072, Yingzhou, Anhui province) Chinese poet, historian, and statesman. He served in various official positions but was repeatedly demoted or banished for his outspokenness. He called him¬ self Zuiweng (“Old Drunkard”), built a pavilion of that name, and wrote an essay about it that is one of the most celebrated works in Chinese literature. Later put in charge of civil-service examinations, he favoured those who wrote in the simple, ancient style known as guwen and failed those who used literary embellishments, thus setting a new course in Chinese litera¬ ture. His own writings in the guwen style, including Xintangshu (1060; “New History of the Tang Dynasty”), became a model that was long emu¬ lated. When the Xintangshu was finished, Ouyang was rapidly promoted to the highest councils of state, leaving a remarkable record in social, finan¬ cial, and military affairs. He was falsely accused of having an affair with his daughter-in-law, a charge that injured his prestige. He repeatedly asked to be relieved of his duties, but instead he was sent to be magistrate succes¬ sively in Anhui, Shandong, and Henan. As the leader of the reform move¬ ment of poetry and prose in the Northern Song dynasty, Ouyang established a monumental reputation by his epoch-marking creative works, and he is renowned as one of the Eight Great Masters of Tang and Song.